A shell hit a house in North Sinai's Sheikh Zuweid city, leaving one dead and four injured, the state news agency MENA said.
The deceased and injured were taken to hospital, MENA cited medical sources as saying.
The source of the shell is unknown.
Militancy inside Egypt has seen a significant rise since July 2013, with most attacks targeting Egyptian security forces in North Sinai, although civilians have been affected.
Clashes on Wednesday night between security forces and purported members of the Sinai-based Ansar Bayt al-Maqdis left six of the suspected militants dead, a military source said.
The clashes occurred south of Sheikh Zuweid, the source told Aswat Masriya, adding that security forces also arrested nine suspects.
Ansar has claimed responsibility for numerous attacks. The group pledged allegiance to the leader of the Islamic State fighters in Iraq and Syria in a video released in November 2014, after Islamic State fighters gained control over large areas of Iraq and Syria over the summer of 2014.
Amid an intensified campaign to counter insurgency, the army said, it killed over 300 suspected militants in security campaigns in North Sinai during the months of February, March and April, in a number of separate statements.
