Hamas, which controls the Gaza Strip, has claimed responsibility for both attacks and linked them to the relaunch of direct Israeli-Palestinian talks in Washington, which it vehemently opposes.
Security forces scoured the occupied West Bank for the gunmen and an Israeli official, who asked not to be named, hailed the Palestinian Authority for what he said was the arrest of hundreds of "terrorists" in the territory.
Hamas gave conflicting accounts of the number of its members arrested in the crackdown, with the leadership in Gaza putting it at 550 but a senior Hamas official in the West Bank saying it was closer to 150.
The Palestinian Authority denied it had arrested any Hamas members in connection with the attacks.
Its security spokesman Adnan al-Damiri said that Hamas members were given "routine summonses which the security services undertake to prevent any law-breaking."
The Western-backed Palestinian Authority and Hamas have been fiercely divided since the Islamist movement seized control of the Gaza Strip in deadly street fighting in 2007.
A military spokeswoman said Israeli forces had arrested eight "wanted Palestinians" in and around Hebron, where the first attack took place, but declined to say whether the arrests were related to the incident.
Major Peter Lerner, an Israeli military spokesman, had earlier said that while Israel had a "good working relationship" with Palestinian security forces there was still the risk of future attacks.
"They are working against Hamas and we are working against Hamas, but it's still not enough and the results are plain to see over the last two days," Lerner told reporters on a tour of the West Bank.
"All it takes is one man with a gun, one man, to penetrate our defences."
Israeli Prime Minister Benjamin Netanyahu and Palestinian president Mahmud Abbas, who were in Washington for the talks, both condemned the attacks.
"I will not let the terrorists block our path to peace, but as as these events underscore once again, that peace must be anchored in security," Netanyahu said Wednesday.
Abbas called for an end to the violence.
"We do not want at all that any blood be shed... one drop of blood on the part of Israelis and Palestinians," he said.
Furious settlers vowed to flout an Israeli moratorium on West Bank settlement construction in protest at the attack.
In a symbolic protest, settlers began building a house in the settlement of Beit Haggai, where the slain Israelis were from, after laying the foundation for a sports centre in the West Bank north of Jerusalem on Wednesday.
In November, the Israeli government, under US pressure, imposed a partial, 10-month moratorium on settlement construction in the West Bank outside annexed Arab east Jerusalem in a move aimed at promoting the peace talks.
The Palestinians say that a renewal of settlement building after September 26, when the moratorium expires, would end the negotiations.
But Netanyahu has told US Secretary of State Hillary Clinton that there is "no change to the cabinet decision to end the (moratorium) at the end of September 2010," his office said.
This week's attacks were the first in the West Bank to be claimed by Hamas since early 2008 and followed the deployment of thousands of US-trained Palestinian security forces in the territory over the past three years.
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Security forces scoured the occupied West Bank for the gunmen and an Israeli official, who asked not to be named, hailed the Palestinian Authority for what he said was the arrest of hundreds of "terrorists" in the territory.
Hamas gave conflicting accounts of the number of its members arrested in the crackdown, with the leadership in Gaza putting it at 550 but a senior Hamas official in the West Bank saying it was closer to 150.
The Palestinian Authority denied it had arrested any Hamas members in connection with the attacks.
Its security spokesman Adnan al-Damiri said that Hamas members were given "routine summonses which the security services undertake to prevent any law-breaking."
The Western-backed Palestinian Authority and Hamas have been fiercely divided since the Islamist movement seized control of the Gaza Strip in deadly street fighting in 2007.
A military spokeswoman said Israeli forces had arrested eight "wanted Palestinians" in and around Hebron, where the first attack took place, but declined to say whether the arrests were related to the incident.
Major Peter Lerner, an Israeli military spokesman, had earlier said that while Israel had a "good working relationship" with Palestinian security forces there was still the risk of future attacks.
"They are working against Hamas and we are working against Hamas, but it's still not enough and the results are plain to see over the last two days," Lerner told reporters on a tour of the West Bank.
"All it takes is one man with a gun, one man, to penetrate our defences."
Israeli Prime Minister Benjamin Netanyahu and Palestinian president Mahmud Abbas, who were in Washington for the talks, both condemned the attacks.
"I will not let the terrorists block our path to peace, but as as these events underscore once again, that peace must be anchored in security," Netanyahu said Wednesday.
Abbas called for an end to the violence.
"We do not want at all that any blood be shed... one drop of blood on the part of Israelis and Palestinians," he said.
Furious settlers vowed to flout an Israeli moratorium on West Bank settlement construction in protest at the attack.
In a symbolic protest, settlers began building a house in the settlement of Beit Haggai, where the slain Israelis were from, after laying the foundation for a sports centre in the West Bank north of Jerusalem on Wednesday.
In November, the Israeli government, under US pressure, imposed a partial, 10-month moratorium on settlement construction in the West Bank outside annexed Arab east Jerusalem in a move aimed at promoting the peace talks.
The Palestinians say that a renewal of settlement building after September 26, when the moratorium expires, would end the negotiations.
But Netanyahu has told US Secretary of State Hillary Clinton that there is "no change to the cabinet decision to end the (moratorium) at the end of September 2010," his office said.
This week's attacks were the first in the West Bank to be claimed by Hamas since early 2008 and followed the deployment of thousands of US-trained Palestinian security forces in the territory over the past three years.
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