US Secretary of State Condoleezza Rice warned Iran that Washington had beefed up its security presence in the Gulf and would not hesitate to defend Israel and other allies in the region. "We will defend American interests and the interests of our allies," Rice said, answering a question on an Iranian threat to "set fire" to Israel. "We take very strongly our obligation to defend our allies and we intend to do that," she said at a news conference in Tbilisi. "In the Gulf area, the United States has enhanced its security capacity, its security presence and we are working closely with all our allies... to make (sure) they are capable of defending themselves," she said. The comments by the United States' top diplomat came after Iran again ratcheted up its rhetoric against the West and test-fired a series of missiles on Wednesday and Thursday. One of the missiles tested has the range to reach Israel and US bases in the Gulf.