Plans to strike Iran "ready", says U.S. Israel envoy

(Reuters) - U.S. plans for a possible military strike on Iran are ready and the option is "fully available", the U.S. ambassador to Israel said, days before Tehran resumes talks with world powers which suspect it of seeking to develop nuclear arms.

Like Israel, the United States has said it considers military force a last resort to prevent Iran using its uranium enrichment to make a bomb. Iran insists its nuclear programme is for purely civilian purposes.

"It would be preferable to resolve this diplomatically and through the use of pressure than to use military force," Ambassador Dan Shapiro said in remarks about Iran aired by Israel's Army Radio on Thursday.

"But that doesn't mean that option is not fully available - not just available, but it's ready. The necessary planning has been done to ensure that it's ready," said Shapiro, who the radio station said had spoken on Tuesday.

The United States, Britain, France, Russia, China and Germany have been using sanctions and negotiations to try to persuade Iran to curb its uranium enrichment, which can produce fuel for reactors, medical isotopes, and, at higher levels of purification, fissile material for warheads.

New talks opened in Istanbul last month and resume on May 23 in Baghdad.

Israel, which is widely assumed to have the Middle East's only atomic arsenal, feels threatened by the prospect of its arch-foe Iran going nuclear and has hinted it could launch pre-emptive war.

But many analysts believe the United States alone has the military clout to do lasting damage to Iran's nuclear programme.

In January, Shapiro told an Israeli newspaper the United States was "guaranteeing that the military option is ready and available to the president at the moment he decides to use it".

U.S. lawmakers are considering additional legislation that would increase pressure on Iran, with further measures to punish foreign companies for dealing with Iran in any capacity.

(Writing by Maayan Lubell; Editing by Andrew Roche)