The head of the UN nuclear monitoring agency warned Syria in comments published Sunday of negative consequences if it does not cooperate with the agency's investigation of its nuclear activities. The London-based Al Hayat newspaper quoted International Atomic Energy Agency chief Mohamed ElBaradei as saying in an interview that it is in Syria's interest to cooperate. Otherwise, Syria will face a deeper confrontation with the international community, ElBaradei said, according to the paper. The pan-Arab newspaper quoted him as saying that his agency still expects clarifications from Syria and Israel on issues related to a Syrian site bombed by Israel last year that allegedly had features resembling a nuclear reactor. IAEA inspectors found traces of processed uranium at the site during a visit this year. Syrian officials said the discovery was not an indication that Syria was building a nuclear reactor. Syria's foreign minister has suggested that the traces may have been from Israeli bombs dropped on the site in the Sept. 6, 2007, airstrike. ElBaradei said the agency has sent a letter to Israel requesting clarifications on the Syrian claim. "We are also looking into technical aspects to see whether it really was from the Israeli attack," he said. "We have not received a reply from the Israeli or Syrian side," he added. Syria has signaled it will not permit IAEA inspectors to return to the country after their initial visit to the bombed site in June. Syria is also refusing to allow visits to three other locations the IAEA regards as suspicious. US officials have said the Al-Kibar facility was a nearly completed reactor of North Korean design that could have produced plutonium, a pathway to nuclear arms. Syria denies it has any nuclear ambitions and says the site was an unused military installation. In the interview with the newspaper, the IAEA chief said the agency would like to hold a meeting with the Syrians soon to discuss the source of the uranium found and other technical issues. "I hope Syria will cooperate with us because that will be in its best interest. Lack of cooperation will ... lead to more confrontations and a negative reaction from the international community," he was quoted as saying. "If it (Syria) has nothing to hide, I don't see any reason for not being 100 percent transparent with the agency," ElBaradei added. ElBaradei also said the August killing of a Syrian official participating in the agency's investigation has complicated the agency's work. Arab media have said Brig. Gen. Mohammed Suleiman was killed by a sniper on a yacht at a beach resort in the northern port city of Tartous. Syrian officials have confirmed his death but gave no other details. ElBaradei said Suleiman was the IAEA's contact on the Syrian side. "Yes, he was our contact, and he was killed. ... His death of course has further complicated matters," he said.