Israel has put on hold a large arms deal with Venezuela following a US demand to curb military cooperation with the regime of Hugo Chavez, who has been a vocal critic of the Bush administration. According to Israeli sources, the American demand was presented several months ago at a time when military ties between Israel and the US were troubled because of the sale of "Harpy" UAVs to China. The deal that was stopped includes the upgrade of F-16 fighter jets of the Venezuelan air force. The upgrade was to have been done by Israel Aircraft Industries (IAI), but Israel asked the Pentagon for consent because the F-16 is an American-made platform. The Israeli sources added that it was not clear yet if the deal was only delayed on a temporary basis or if it would be canceled altogether. American and Israeli representatives held talks in the past weeks in an attempt to clarify the US position regarding the Venezuelan deal and to allow it to go through. Defense Minister Shaul Mofaz is scheduled to visit Washington next month and is expected to raise the issue of Israeli arms sales with his American counterparts. Venezuela's President Hugo Chavez has been among the most critical world leaders of US policy under President George W. Bush. Chavez has also partnered with Cuban leader Fidel Castro, who represents extremist opposition to the US in Latin America. The arms sales crisis between Israel and the US was resolved last August after Mofaz and US Secretary of Defense Donald Rumsfeld signed a memorandum of understanding setting out new rules for control of arms sales from Israel to third countries. The US halted most of its defense cooperation with Israel after learning that Israel had begun a major upgrade deal for "Harpy" UAVs sold to China. IAI officials could not be reached for comment on the report. The upgrades were to be carried out by IAI's Lahav division, which has a rich tradition of upgrading F-16s and other US-made fighter jets. These include advanced avionics, electronic warfare suites and "smart bomb" integration. It was not clear where the deal with Venezuela stood, but it was not considered very large since its fleet of F-16s is relatively small. Venezuela has some 24 F-16A and six F-16B models, all purchased from the US over 20 years ago. Israel has sold Venezuela radar, air defense missiles and Litening pods used by fighter jets to target air-to-ground missiles, according to Tel Aviv University's Jaffee Center for Strategic Studies' The Middle East Strategic Balance. Arieh O'Sullivan contributed to this report.