The Israel Defense Forces (IDF) bolstered its presence around the Gaza Strip and Tulkarem on Monday to prepare for a possible Palestinian reprisal for the killing of one senior militant leader in a West Bank raid, Israel Radio said.

Israeli Defense Minister Shaul Mofaz instructed the IDF to be on high alert and ready to respond to any incidents, said the radio.

Meantime, IDF troops were still operating in the Tulkarem camp and nearby refugee camps. Local reports said troops had surrounded two houses, and quoted Palestinian sources as saying that six people had been arrested there.

In raids elsewhere in the West Bank, IDF troops arrested some 20 wanted Palestinians overnight Sunday, most of them members of Hamas, the radio reported.

Earlier Monday, Islamic Jihad vowed "blood for blood" in response to the IDF operation, which also killed a top Al-Aqsa Martyrs Brigades member.

The Palestinian National Authority (PNA) on Monday slammed the raid as counter-productive.

"We condemn the Israeli incursion and assassinations in Tulkarem. This threatens the cease-fire we're trying to maintain," chief Palestinian negotiator Saeb Erekat said.

Abu Abdallah, a spokesman for the Islamic Jihad military wing in Gaza, vowed that the group's retaliation for this crime "will be unprecedented."

"We will not stand handcuffed while the blood of our fighters is being shed... Let calm go to hell," said a statement by the group.

Source: Xinhua