RAMALLAH, Palestinian Territories (AFP) - Israeli forces shot dead two Palestinians in the West Bank as they continued a search for three missing Israeli teens, Palestinian medical and security officials said on Sunday.

In Ramallah, 30-year-old Mohammed Tarifi was shot dead during early morning clashes with Israeli troops near the city centre in which five other Palestinians were wounded, medics told AFP.

In Ein Beit al-Mai refugee camp in western Nablus, 27-year-old Ahmed Fahnawi was shot and killed on his way to a mosque for morning prayers as clashes were taking place, security officials told AFP.

Family members said he was mentally unsound.

The Israeli army had no immediate information on the Ramallah incident, but confirmed firing at a man in Nablus who had approached the troops "in a threatening manner".

When he failed to respond to warning shots fired in the air, they fired towards him. "Initial inquiry suggests that the suspect was mentally unstable," the military statement said.

Clashes erupted in the two areas when Israeli forces arrived to conduct arrests as part of the operation to locate the three teenagers they believe were abducted by Islamist movement Hamas on June 12.

An army spokesman told AFP that six suspects were arrested overnight, bringing the total number of Palestinians held since the beginning of the operation to over 340, around two thirds of them Hamas members.