KFAR MAIMON, Israel (Reuters) - Israeli right-wingers clashed on Tuesday with police who blocked thousands of protesters from marching on Gaza settlements and trying to disrupt Israel's pullout from the occupied strip.

Demonstrators ignored orders to disperse as security forces penned them inside the southern Israeli farming village of Kfar Maimon to prevent them from advancing any further toward the Gush Katif settlement bloc, about 15 km (9 miles) to the west.

It was the biggest showdown so far with protesters opposed to Prime Minister Ariel Sharon's pullout plan and could be a preview of confrontations expected when Israel begins evacuating 21 settlements in Gaza and a pocket of the West Bank next month.

In the Gaza Strip, Palestinian President Mahmoud Abbas's Fatah party and Hamas were reported to have agreed to try to end the worst internal Palestinian fighting in years.

In the Israeli right-wing protests, 16 people were arrested and several were injured when demonstrators shouting "Police state" and vowing to defy a ban on their march tried to push through a police cordon.

Police and angry youths traded punches. Officers on horseback moved into the crowd. Water cannon were brought in but not used.