The Israeli army said Hamas members were among another 20 activists arrested in West Bank cities such as Jenin and Nablus on Tuesday.
On Monday, security sources said they had smashed three Hamas cells, each containing several dozen members, that had been planning attacks against Israel and been behind the kidnapping and killing of an Israeli.
Israel’s Deputy Prime Minister Shimon Peres said it was in the common interests of Israel and the Palestinian Authority to prevent Hamas strengthening its base in the West Bank.
“We deeply dread the idea that the terrorism will move from Gaza to the West Bank which is why we are carrying out preventive operations,” Mr Peres said in reference to the mass arrest campaign in the West Bank.
Israel should be unwavering in its support of Palestinian leader Mahmoud Abbas, he said.
Mr Abbas had been due to meet Israeli Prime Minister Ariel Sharon on Tuesday but the summit was dropped when preparatory talks failed.
The main sticking point was Palestinian calls for Israel to release long-serving Palestinian prisoners and for Israeli troops to pull away from West Bank cities.
Mr Sharon, at a reception to mark the Jewish New Year, urged the Palestinians to keep their commitments to the peace process.
“We have a plan which has been accepted by the cabinet, the roadmap, which can be implemented if the Palestinians keep their commitments, and I intend to work for that,” he said.
Israel says Mr Abbas has not done enough to crackdown on militant groups such as Hamas since the departure of its troops from the Gaza Strip a month ago.
Mr Peres, a dove in Sharon’s coalition government, said it was important that Israel does all it can to bolster Mr Abbas’s position.
“It is crystal clear that we must show no compromise in our fight against Hamas and support Abu Mazen (Abbas),” the Labour leader told public radio.
“This is a battle between fanatical groups of extremists and murderers, such as Hamas and al-Qaeda, and men of reason, people with whom one can talk and negotiate,” he said.
Mr Peres said it was vital the security services prevent Hamas radicals from transforming the West Bank into their new stronghold.
Israel has threatened to disrupt next January’s Palestinian legislative elections if Hamas — which refuses to recognise the Jewish state’s right to exist — participates.
A recent poll showed Mr Abbas’s Fatah faction was on course for a victory in January with 45.6 percent, against 23 percent for Hamas, which is fielding candidates for the first time.