Israeli soldiers shot dead two Palestinians in the West Bank early on Sunday in separate clashes as Israel continued its crackdown on Hamas in the wake of the alleged disappearance of two Israeli teenagers.

The deaths raised to four the number of Palestinians killed since the Israeli army began raiding Palestinian areas and arresting hundreds of people, mostly members of Hamas, over a week ago.

Israel says it is searching for two teenagers who disappeared on June 12 while hitchhiking in the southern West Bank. Israel accuses Hamas militants of kid-napping them but has not provided any evidence.

Israel has said the objective of "Operation Brother's Keeper" is to bring the teens home safe while dealing a crushing blow to the West Bank infrastructure of its Islamist nemesis.

So far, the army has arrested more than 340 Palestinians, around two-thirds of them members of the Islamist movement.

Rising death toll

With the search entering its 10th day, clashes broke out in the northern cities of Nablus and Ramallah as troops went in to carry out arrests, sources on both sides said.

Troops in Ein Beit al-Mai refugee camp in western Nablus shot dead 27-year-old Ahmed Fahnawi as he was on his way to a mosque for morning prayers as clashes were taking place.

Palestinian security sources said he was hit by four bullets, while family members said he was mentally challenged. The Israeli army confirmed firing at a man, saying he had approached troops "in a threatening manner".

Also early on Sunday, Israeli troops shot dead 30-year-old Mohammed Tarifi during clashes that lasted for hour sin the center of Ramallah, the West Bank's political capital, Palestinian medics said. Five others were also wounded during the incident, they said.

In West Bank clashes earlier in the week, Israeli troops shot dead two Palestinian teenagers and another young man was left fighting for his life.

The teens' alleged seizure has been condemned by Palestinian President Mahmoud Abbas. However, on Sunday, he questioned why Israeli Prime Minister Benjamin Netanyahu had not condemned the bloodshed triggered by the manhunt.

"I said the kidnapping was a crime, but does that justify the killing of...Palestinian teens in cold blood?" Abbas said in an interview with Haaretz news-paper, referring to the deaths of two young Palestinians.