At least six Israeli soldiers have been wounded when mortars fired by Palestinian fighters from Gaza landed in a military base in southern Israel.

Israel's rescue service said one of the soldiers was critically injured, and the others were slightly or moderately hurt.

According to the Israeli military, armed Palestinians fired a total of 11 mortars at southern Israel on Friday. Three of them landed at the base in the western Negev desert.

There was no immediate claim of responsibility from any Palestinian group.

Earlier in the day, Palestinian gunmen clashed with Israeli troops elsewhere along the volatile Gaza-Israel border.

Gaza's ruling Hamas faction said two of its fighters were wounded in an Israeli air strike.

The violence is further marring a five-month-old truce between Israel and Gaza rulers that began breaking down in early November.

The truce was meant to be renewed next month, and its fate is unclear.

Armed Palestinians have fired dozens of rockets and mortar bombs at Israel in the past three weeks after Israel launched raids that killed about a dozen gunmen, and closed crossing points with Gaza, choking off some food supplies to the coastal territory.