An Israeli air strike killed two Palestinians on Tuesday in the southern Gaza Strip, where mortar bombs were fired at Israel earlier, witnesses and hospital officials said.

The Israeli army confirmed the air strike in the town of Rafah, which wounded two people, and said militants had launched six mortar bombs across the border.

Witnesses and hospital officials said two Palestinians were killed in the Israeli attack. Relatives said both were civilians and one was aged 15.

Hamas, an Islamist group that controls the Gaza Strip, said one of its members was wounded in the incident.

Militants have fired dozens of rockets and mortar bombs at Israel in the past three weeks after Israeli raids that killed about a dozen gunmen.

The violence has strained a ceasefire in place since June. Saying it was responding to rocket attacks, Israel has tightened its closure of Gaza borders, choking off some food supplies to the territory and raising international concern.