Israeli forces searching for three teenagers believed to have been kidnapped swept into a second West Bank city on Monday, June 16 touching off street confrontations in which they killed a Palestinian, witnesses and hospital officials said, according to Reuters.

The bloodshed near the de facto Palestinian capital of Ramallah marked an escalation in a dragnet targeting Hamas, an Islamist group which earlier this month agreed to form a unity government with U.S.-backed Palestinian President Mahmoud Abbas.

Witnesses said Palestinians threw rocks at soldiers conducting house-to-house searches in al-Jalazoun refugee camp, outside Ramallah, before dawn. Army gunfire killed a 20-year-old Palestinian and wounded another, hospital officials said.

The military, which had announced plans to step up its West Bank operations to locate the three Israeli teens who disappeared after leaving a Jewish settlement on Thursday, said it was checking reports on the al-Jalazoun incident.

Israel accuses Hamas militants of abducting the three youths and has rounded up scores of Palestinians in Hebron, a West Bank city where support for the Islamist faction is strong.

The military said on Monday troops had detained 40 Palestinians across the West Bank overnight, "including Hamas leadership and operatives", bringing up to 150 the number of arrests since the search operation began.

Among the detainees were several Palestinian lawmakers from Hamas, including parliament speaker Aziz Dweik, witnesses said.

Israeli Deputy Foreign Minister Tzachi Hanegbi said the search was being conducted in the wider Hebron area and that forces have not yet zeroed in on a particular neighborhood.

"Time is always a negative factor, the more goes by the less positive it is, but our working assumption ... is that the boys are alive and we are exerting every effort to reach them," Hanegbi told Israel Radio.

The crisis is a severe test for Abbas. His security forces have sought to help Israel's search, drawing censure from Hamas.

Israeli Prime Minister Benjamin Netanyahu called off meandering U.S.-sponsored peace talks with Abbas in response to the Palestinian unity deal, which he says emboldened Hamas and its belligerence toward Israel.

"I believe that the dangers of this pact should now be abundantly clear to all. We've seen since the signing of that pact an increase in terrorist activity emanating from the West Bank," Netanyahu said on Sunday, blaming Hamas for abducting the three teenagers and holding Abbas responsible for their return.

Hamas has neither confirmed nor denied Israel's allegation. Some Palestinians close to Abbas accused Netanyahu, who champions Jewish settlement of occupied West Bank land where they seek statehood, of seeking a pretext for further hostility.

On Saturday and Sunday, several rockets were fired into Israel from the Gaza Strip, a Palestinian territory where Hamas holds sway. Israel launched air strikes at training camps used by Hamas and Islamic Jihad, another Palestinian militant group.

There were no serious casualties on either side.