US Attorney-General Alberto Gonzales on Tuesday warned that the war against terrorism was evolving and that a new threat was in the making from homegrown terrorism, which was sometimes harder to defend against than international terrorism. "They [home-grown terrorists] are much more difficult to find because they exist in our communities," said Gonzales in a speech at Tel Aviv University's Jaffe Center for Strategic Studies, during a short visit to Israel which was due to end Wednesday. "This is presenting additional challenges for us that we are now beginning to focus on." Asked whether he thought the war against terrorism was succeeding, Gonzales replied, "The US and other countries, like Israel are safer today. [But] we are not safe." Gonzales singled out US-Israel collaboration in combatting terrorism. "We are working closing in the war on terror," he said. Gonzales that the improvement in US security was due to the establishment of the Homeland Security Department, new legislation such as the Patriot Act, the war against terrorism in Afghanistan and Iraq and strong international cooperation among law enforcement agencies, which he described as "fantastic." Still, he said, he constantly reads intelligence reports about terrorist threats to the US and other countries, including Israel. "I sometimes wonder when it this ever going to stop," he added. "And it may not stop for a while." Gonzales refused to say whether or not the Bush administration was seriously considering closing the prison facility at Guantanamo Bay. In the meantime, the US government is awaiting a Supreme Court ruling on a petition challenging the commissions established by the government to try some of the detainees imprisoned at the US facility. Gonzales said the US had already released more than 300 detainees arrested since January 2002. He added that one of the problems preventing more detainees from being set free was that no country wanted to take them, and they would be in danger if they returned to their native countries. He gave an example of 16 Chinese detainees that the US did not want to repatriate for fear they would be tortured by Chinese authorities. Human rights groups in the US have charged that many of the detainees at Guantanamo have been tortured or treated in a cruel, inhumane and degrading manner and in violation of international human rights law. According to Gonzales, prisoners at Guantanamo receive "top-notch medical care, they receive good food, and good facilities." Gonzales was also asked why the US refused to join the International Criminal Court, which was established to try alleged war criminals. He replied that the US had more at stake than other countries because it had more troops serving around the world and therefore the risk of indictments against US personnel was greater. "No country would enter into an agreement that is contrary to their interests," he said. "Why would a country do that?" Gonzales devoted the formal part of his address to the need for international cooperation in the fight against other transnational crimes in addition to terrorism, such as cyber crimes, drug trafficking, trafficking in humans and child pornography. AP contributed to this report.