LONDON (Agencies) - Israel urged the US to take tougher action against Irans nuclear programme, pressing it to put a deadline on negotiations and to consider a military strike if necessary, according to WikiLeaks documents, reports The Hindu. The confidential US diplomatic cables obtained by the whistleblower website were quoted by the Spanish daily El Pais. Israel sees Iran as the biggest threat to its security, Israeli defence officials told US officials in 2009 the first year of the new US administration under President Barack Obama, citing Tehrans nuclear programme and regional hegemonic ambitions. Not only would Irans acquisition of nuclear weapons allow it to use them against Israel, but it would unleash a nuclear arms race across the Middle East, according to the Israeli assessment. Irans transformation into a nuclear power would be a world-changing event which would make all other issues pale in comparison, Israeli Prime Minister Benjamin Netanyahu is quoted as telling a US senator. Netanyahu pressed Washington say what it would do if Iran reaches the nuclear threshold, pressing the US to move quickly. In 2007, Israeli secret service chief Meir Dagan had underscored the need to prevent technology from reaching Iran, and encouraged Washington to foment a regime change there by supporting student democracy movements and ethnic groups opposed to the regime. The 2007 cable also mentions discussions on covert measures, without giving more details. The meeting took place just a few weeks after the Israeli secret service Mossad reportedly celebrated the killing of an Iranian scientist, El Pais said. Dagan also proposed getting Europe to act tougher on Iran, increasing Voice of America broadcasts in the country, and coordinating with the Gulf States and countries north of Iran to pile up pressure. The US policy to engage with Tehran should only be pursued for a finite period of time, Israeli security experts stressed to a senior US official in July, 2009. All options including a military strike must remain on the table, they said. The window for stopping Irans nuclear programme was rapidly closing, the security experts also maintained at the time, arguing that it would take Tehran only one year to obtain a nuclear weapon and 2.5 years to build an arsenal of three weapons. A 2007 cable mentions the upcoming delivery of GBU-28 bunker busting bombs to Israel, saying the transfer should be handled quietly to avoid any allegations that the US government is helping Israel to prepare for a strike against Iran. In their talks with US officials, Israeli representatives also expressed concern over Russias possible reluctance to fully pressure Tehran over its nuclear programme. US diplomats stressed Washingtons commitment to the diplomatic track and sanctions, but also said the US offer to negotiate with Tehran was not indefinite.