Palestinian police arrested two suspected militants Saturday in connection with a suicide bombing that killed four Israelis at a Tel Aviv nightclub, acting on orders from Palestinian leader Mahmoud Abbas to track down those responsible for what he called an act of sabotage. In a phone call from Lebanon, an official from the Syria-based leadership of the Islamic Jihad militant group claimed responsibility Saturday for the suicide bombing, contradicting a denial issued by the militant group in the Palestinian territories shortly after the beachfront attack late Friday. Israeli security officials said on condition of anonymity they were convinced that Islamic Jihad carried out the attack, with orders coming from headquarters in Syria.The two other main militant groups — Hamas and the Al Aqsa Martyrs Brigades — have denied involvement, as has the Iranian-backed, Lebanese-based Hezbollah. Palestinian security officials had pointed to Hezbollah, which has been trying to disrupt an informal Mideast truce agreed to Feb. 8. "Hezbollah is the one that armed the bomber and gave the orders to carry out the attack," a Palestinian official said on condition of anonymity. He said Hezbollah asked those involved to make a tape saying they carried out the orders in the name of Islamic Jihad. He also said the bomber was an Islamic Jihad sympathizer, but not a member of the armed military wing. Palestinian police arrested two suspected militants in connection with the nightclub bombing, and local security officials in the northern West Bank town of Tulkarem said the suspects had ties to Islamic Jihad. The bomber was identified as Abdullah Badran, 21, a university student from the village of Deir al-Ghusun near the West Bank town of Tulkarem. His parents said he was a devout Muslim with no history of militant activity.