By Ali Sawafta and Crispian Balmer
RAMALLAH West Bank (Reuters) - Israel eased a crackdown on Hamas in the occupied West Bank on Tuesday after the dragnet, accompanying a search for three Israeli teenagers, raised fears of a Palestinian uprising.
Israel has accused the Islamist group of orchestrating the abduction of the Jewish seminary students on June 12, and the Israeli military's raids of Palestinian towns and cities have undermined Western-backed President Mahmoud Abbas.
Up to six Palestinians have died as a result of the military operations, locals say, and some 355 people have been arrested.
A senior United Nations official cautioned on Monday the army action risked provoking a revolt, while Palestinians in the West Bank have turned on Abbas for offering to help Israel find those behind the kidnapping.
With the Muslim holy month of Ramadan set to start on Saturday, an Israeli government official said members of Prime Minister Benjamin Netanyahu's security cabinet had expressed concern that events could "escalate out of control".
Growing international criticism about the impact on ordinary Palestinians has also been taken into account, he said.
"Following this, a decision was made to significantly narrow the operation and focus it on pinpoint actions to return the abductees," said the official, who declined to be named.
The Israeli military said on Tuesday that only four Palestinians had been arrested during overnight operations compared with 37 the day before.
"We are continuing intelligence and operational efforts to bring about the release of the abductees and to get our hands on the kidnappers. That hasn't changed at all," Defence Minister Moshe Yaalon told reporters.
But, acknowledging the number of arrests had dropped sharply over the past day, he said "a large part of the operation" against Hamas had been completed now that dozens of activists were in custody and many of its institutions were closed.
Hamas has declined to deny or acknowledge responsibility for snatching the youths, who vanished while hitchhiking near a Jewish settlement, although it has praised the kidnapping.
Abbas himself denounced those behind the abduction and promised to work with Israel to locate the missing teenagers.
Many Palestinians reacted angrily to Abbas's stance, seeing it as a sign of weakness in the face of the Israeli occupation.
Locals clashed with his security forces in central Ramallah on Sunday, while social media were filled with images of glum policemen watching from a balcony in the city of Hebron as dozens of Israeli soldiers took charge of the streets below.
The Palestinian Authority has self-rule in the major West Bank cities, but the Israeli crackdown has shown the limited scope of its powers, with soldiers carrying out searches and raids just one block from Abbas's own house in Ramallah.
"The Palestinian anger is growing and no-one knows where it will end," said Hazem Abu Hilal, a political activist who has taken part in a number of Ramallah rallies to protest against ongoing security coordination with Israel.
The abduction came two months after the collapse of U.S.-led peace talks between Israel and the Palestinians - the latest in a long line of failed efforts to secure a negotiated end to the generations-old conflict.
It also came fast on the heels of a deal signed by Abbas's Fatah faction and Hamas to overcome seven years of ferocious feuding, opening the way for the formation of a unity government earlier this month.
The future of that administration is now in doubt.
With Israel promising to show more restraint in its operations, political analyst Hani Al-Masri said Abbas and his Palestinian Authority needed to show his people that they were confronting the Israeli occupation, not aiding it.
"The Authority cannot play two games at a time, maintaining security coordination (with Israel) and defending the people," Masri said. "It has to choose to defend its people and chase Israel through diplomatic means at the United Nations. If it does not do that, it will fall," he added.
(Additional reporting by Nidal al-Mughrabi in Gaza and Maayan Lubell in Jerusalem; Editing by Jeffrey Heller and Ralph Boulton)