Israeli aircraft struck a Palestinian rocket launching pad and an unidentified militant activity site in the Gaza Strip early Monday, in response to persistent rocket and mortar fire from the coastal territory, the military said.

Gaza militants launched 11 rockets and mortars into southern Israel earlier in the day, according to the military's count. No casualties were reported on either side.

The hostilities undercut a brittle, informal truce that went into effect last week after the worst outbreak of violence between the two sides in months.

Later Monday, military aircraft dropped leaflets over Gaza warning Palestinians to stay away from the border fence with Israel or risk drawing live fire.

The leaflets also warned civilians not to cooperate with militants, dig underground smuggling tunnels or smuggle in weapons.

In Gaza, Palestinian police with the strip's ruling militant Hamas movement scooped up the leaflets.