The issue of what to do about the world's 65.3 million displaced people takes center stage at the United Nations General Assembly Monday when leaders from around the globe converge on New York for the first-ever summit on Addressing Large Movements of Refugees and Migrants.

Islamic State militants shot down a Syrian warplane on Sunday as Syrian forces regained ground lost to the extremists following a U.S.-led airstrike that hit government forces the day before, state media said. The U.S. military says it may have unintentionally struck Syrian troops while carrying out a raid against IS in eastern Syria on Saturday. The incident has threatened an already fragile U.S. and Russian-brokered cease-fire that has largely held despite dozens of alleged violations on both sides. Opposition monitoring groups said warplanes struck rebel-held neighborhoods in the northern city of Aleppo for the first time since the cease-fire went into effect on Monday, wounding several people. In southern Syria, government helicopters dropped barrels bombs on a rebel-held village, killing eight people. Moscow laid the blame squarely on the opposition after activists reported the strikes. Russian Defense Ministry spokesman Maj. Gen. Igor Konashenkov said in an emailed statement that both "terrorists and the opposition" are using the truce to "boost their forces and prepare for renewed hostilities." Konashenkov says Moscow still has not been able to contact the U.S.-backed opposition to coordinate cease-fire efforts despite Washington's assurances. He says the U.S. has not even tried to get the opposition to hold its fire. Syria meanwhile called Saturday's U.S.-led airstrikes on the outskirts of the eastern city of Deir el-Zour a "dangerous and blatant aggression against the Syrian Arab Republic and its army." The Foreign Ministry's statement, sent to the presidents of the United Nations and the U.N. Security Council, said American warplanes repeatedly attacked Syrian army positions on Saturday afternoon. It said the airstrikes were "on purpose and planned in advance," and killed dozens of Syrian soldiers. Russia's military said it was told by the Syrian army that at least 62 soldiers were killed in the Deir el-Zour air raid and more than 100 wounded. The Russian air force has been carrying out strikes across Syria to bolster President Bashar Assad's forces for nearly a year, and the two militaries work in close coordination. The Britain-based Syrian Observatory for Human Rights, which relies on a network of activists inside Syria, said the U.S.-led coalition struck army positions in Tharda mountain and a nearby artillery division, killing 90 troops and wounding 110. Russia said the United States was being obstructive and deceptive regarding the airstrike. A Foreign Ministry statement on Sunday said that in an emergency U.N. Security Council session the United States took "an unconstructive and indistinct position." The Americans "not only turned out to be unable to give an adequate explanation of what happened, but also tried, as is their custom, to turn everything upside down," the statement said. Iran, another close ally of Syria's government, also condemned the U.S. raid, saying it violated Syria's sovereignty and "showed that terrorist groups enjoy U.S. support in Syria." Earlier Sunday, the Syrian state-run SANA news agency quoted an unnamed military official as saying that dozens of IS fighters were killed in the air and ground offensive on Tharda mountain. IS had claimed that its fighters captured Tharda mountain, which overlooks the city's government-controlled airport. The Syrian military official said government troops had regained control of areas the extremists captured "as a result of the American aircraft aggression." State TV later reported that a Syrian warplane was shot down while carrying out attacks on IS militants in the Deir el-Zour province, adding that the pilot was killed. IS-linked media also reported the incident. The Observatory confirmed the downing of the Russian-made MiG warplane over Tharda mountain. It said that intense airstrikes by Russian warplanes have killed at least 38 IS fighters since Saturday. The Syrian military said the coalition airstrike hit a base in Deir el-Zour that was surrounded by IS, allowing the extremists to advance and overrun Syrian army positions in the area. Tens of thousands of people live in government-held neighborhoods of Deir el-Zour under an IS siege. Government areas have been relying on airlifted aid. IS also controls much of the surrounding province, which borders Iraq. Also Sunday, the Syrian government and opposition reported violations of the cease-fire that went into effect on Monday. The cease-fire does not include IS and al-Qaida-linked militants. The Syrian army said in a statement last week that the seven-day truce ends at midnight Sunday. Syrian state media said insurgents shelled residential areas in the northern city of Aleppo and the central province of Homs. The opposition's Local Coordination Committees also reported that government warplanes attacked the central rebel-held town of Rastan. The Observatory and Ahmad al-Masalmeh, an opposition activist based in the southern province of Daraa, said government helicopter gunships dropped barrel bombs on the village of Dael, killing six and wounding a large number of people. In Aleppo, warplanes fired missiles at three neighborhoods, wounding several people, according to the LCC and the Observatory. Also on Sunday, some four million students headed to 15,000 schools for the start of a new school year, state media said. Syria's five-year conflict has damaged hundreds of schools and forced thousands of young Syrians to drop out.

A Libyan force ousted a week ago from key oil ports counter attacked on Sunday, taking back control of Es Sider terminal and triggering clashes near Ras Lanuf port, a spokesman for the force, Ali al-Hassi, and a port worker said.

Russians voted in parliamentary polls on Sunday, with parties loyal to President Vladimir Putin set to maintain their dominance as the Kremlin sought to make a show of eliminating vote fraud after mass opposition protests last time around.

Iran's President Hassan Rouhani said Tehran supports any move to stabilize the global oil market and lift prices, the Iranian oil ministry news agency SHANA quoted him as saying on Sunday.

Two gunmen on a motorcycle killed three soldiers Sunday near the northwestern city of Peshawar, police said.

Unidentified gunmen killed two Saudi policemen in the mainly Shiite eastern city of Dammam late on Saturday, the interior ministry said, describing it as a "terrorist attack".

An explosion rocked the Chelsea neighborhood of Manhattan on Saturday night, injuring at least 29 people, authorities said, adding that they are investigating the blast as a criminal act not immediately linked to any terror organization.

The death toll from a Taliban suicide bomb attack on a mosque in northwest tribal Pakistan rose to 30 on Saturday, officials said.

Pope Francis has encouraged Europeans to welcome refugees, calling authentic hospitality "our greatest security against hateful acts of terrorism."

Israeli occupation forces shot dead a Palestinian who allegedly stabbed an Israeli soldier Saturday in the flashpoint West Bank city of Hebron, the army claimed, in the fourth spate of violence in less than 24 hours.

Air strikes and clashes tested a fragile ceasefire in Syria into Saturday as civilians waited for aid and tensions mounted between the deal's brokers Russia and the United States.

fighting and clashes between regime forces and rebels rocked the eastern edge of Syria's capital on Friday, an AFP correspondent and military source said, despite a fragile truce across the country. "The Syrian army is blocking an attack by armed groups that tried to enter the capital's east via Jobar... leading to intense clashes and rocket fire," a military source told AFP.

Thousands of people protested in Mexico City on Thursday, demanding that President Enrique Pena Nieto resign over his handling of drug violence, corruption and his meeting with Donald Trump.

Iranian President Hassan Rouhani set off Friday for a tour of Venezuela and Cuba before heading to New York for next week's UN General Assembly, official media reported.

The British embassy in the Turkish capital Ankara will be closed on Friday over security concerns, it said, after a spate of attacks that have left Turkey on edge.

If U.S. Republican presidential candidate Donald Trump wins the election in November, it would be problematic for the entire world and encourage copycats in Europe, European Parliament President Martin Schulz told a German magazine.

The UN Syria envoy on Thursday urged the Damascus government to allow humanitarian aid deliveries "immediately", indicating the regime had broken its pledges on the distribution of life-saving supplies.

The United States will give Israel $38 billion in military assistance over the next decade, the largest such aid package in U.S. history, under a landmark agreement signed on Wednesday.

Libya's National Oil Corporation will lift force majeure at three ports seized days earlier by eastern forces, and exports will resume immediately at two of the ports, it said on Thursday.

Former Israeli president and Nobel Peace Prize winner Shimon Peres saw "real improvement" on Thursday but remained in serious condition after the 93-year-old suffered a major stroke, his doctor said.