Prime Minister Ariel Sharon vowed Monday to press Israel's assault on Hamas. With the peace effort stumbling, Palestinian Prime Minister Mahmoud Abbas went to the Gaza Strip for a desperate push to persuade Hamas and Islamic Jihad to stop the intifadha. After a week of violence highlighted by Israeli airstrikes aimed at killing Palestinians and a Hamas bomb attack in Jerusalem, with dozens of casualties on both sides, there were concerns that further delays and violence could bury the U.S.-backed "road map" to peace and a Palestinian state. Egyptian mediators returned to Cairo on Monday after failing to win over the Hamas and Islamic Jihad - whose latest demand appears to be a guarantee that Israel will stop its targeted killings of their members and leaders. However, Palestinians involved in the talks said Egypt would invite all the factions to Cairo for more talks. Previous rounds in Cairo have not produced results. After Monday's session, top Hamas official Ismail Abu Shanab said it was premature to talk about a cease-fire. "Now is not a time for truce. It is time for solidarity and standing united against Israeli attacks on our people," he said. A source close to the talks said U.S. mediators would press Israel to agree to end the targeted killings, and that if this succeeded, the militant groups would then agree to a truce. The source, who spoke on condition of anonymity, said the Egyptians were asking for a written American guarantee of Israel's commitment on this issue, and on troop withdrawals and other steps implementing the road map. The State Department underlined that it taking part in the Egyptian mediation. "I'm not encouraging their meetings. I'm not sending them out on meetings," spokesman Richard Boucher said in Washington, adding that even if Hamas agrees to a cease-fire the group must be dismantled. Abbas arrived in Gaza hoping to step up pressure on Hamas, but by late Monday he had not managed to arrange a meeting with the group's leaders, and it appeared the talks would be put off until Tuesday. Abbas met Monday in Gaza with leaders of his Fatah movement, whose own military wing has also been mounting attacks on Israelis. Sharon, meanwhile, drew support from President Bush in holding firm against Hamas. Israeli officials insisted they would continue targeting militants and rejected the idea of a cease-fire that did not include a dismantling of the militias, as called for in the road map. Speaking to the Israeli parliament, Sharon did not mention the cease-fire effort in Gaza and said his government would "pursue and catch every initiator of terrorism and its perpetrators in every place and at every time until victory." He charged that Hamas had unleashed a "new wave of terror," noting Wednesday's bomb attack on a Jerusalem bus that killed 17 people. He said Israel would continue targeting terrorists. He noted the recent helicopter strikes also killed Palestinian civilians, but said, "This was not our intention." **Zionist Air Rids*** Anxious Gazans, tormented by 33 months of unceasing and unrelenting Israeli state terror, have urged the Palestinian Authority to install sirens throughout Gaza in order to forewarn civilians of impending Israeli air raids. Israeli warplanes have been attacking the crowded Gaza Streets for the past few days, killing as many as 27 people, including 10 children. Scores of other civilians were injured and maimed in deadly rocket attacks by Zionist Apache helicopter gunships targeting suspected Palestinian resistance fighters as well as political leaders. Local leaders are arguing that the sirens would give an adequate warning for civilians to seek cover and take proper precautions. Currently, Gazans use primitive and inadequate means for warning against Apache raids such as car honks. **Muslim Students 'Tortured' by Israel*** Two Muslim medical students have returned to the UK, complaining Friday that Israeli interrogators tortured them after being detained in the occupied territories without trace. Tahseen Chaudhry from Birmingham University said he and his colleague Ayaz Ghani were handcuffed and blindfolded and incarcerated in a "medieval dungeon," while being interrogated for 12 hours at a time to make them confess links with terrorism. He said that during their 11-day detention, they were denied any contact with the outside world, despite repeatedly asking to speak to British consular officials, a lawyer, the Red Cross or their families. Chaudry's solicitor, Imram Khan, accused Israel of using "psychological torture" and warned that other British Muslims could face the same treatment if they visited the occupied territories. "What is quite concerning is that the reason for the detention appears to be simply that he was British and a Muslim. There is a huge number of people who could potentially find themselves in a similar position," Khan said in an interview with BBC radio. Chaudry said that he was detained when crossing from Israel into Jordan. "They said I looked suspicious and we were arrested for questioning. That was the only reason given at first." "I was basically shackled, handcuffed and blindfolded and put into an armored car and transported to an interrogation center where I was put in a cell and over the next 11 days taken out in the mornings and interrogated all day," he told the same BBC programme. The medical student said that he was so exhausted that he kept falling asleep, but the Israeli teams "swap over and repeatedly wake you up and question you about why you came to Israel and what you were doping in other Middle East countries." Chaudhry and Ghani, in their fourth year of their medical degree, were touring Syria, Lebanon, Jordan and the West Bank, when they were arrested on May 24. They had been due to fly from Damascus to Dubai on the evening of June 7 but did not catch the flight. Their families have complained that they were not advised by the Foreign Office in London when they disappeared without trace, even though consular officials were told about their arrest within 24 hours. Chaudry said that he was put in a dark cell that measured only two meters by one meter, describing it like a "medieval dungeon." He said that their families had originally been told they had been kidnapped. Their families have also said that they were confused when they were told on June 4 that they were being handed over to Jordanian authorities, who initially denied this for several days. **PHOTO CAPTION*** Senior Hamas leader Ismail Abu Shanab, left, Dr. Mohammed al Hindi a top Islamic Jihad offical, center, and Fatah leader Ahmed Heles, talk with reporters following a meeting with Egyptian mediators Monday, June 16, 2003, in Gaza City. (AP Photo/Rick Bowmer)