Iran says it has carried out a successful test of the latest version of a ballistic missile that defence experts say can reach Israel or US bases in the Gulf.
Defence Minister Mr Ali Shamkhani said last week Iran was working to improve the range and accuracy of the Shahab-3 medium-range in response to Israel's moves to boost its anti-missile capability.
Iran says its missile programme is purely for deterrent purposes. Tehran also denies US and Israeli accusations it is seeking to develop nuclear warheads that could be delivered by the Shahab-3.
In Washington, the State Department said Iran's attempts to improve its missile capability were a threat to the region and US interests.
Based on the North Korean Nodong-1 and modified with Russian technology, the Shahab-3 is thought to have a range of 1,300 kilometres, which would allow it to strike anywhere in Israel.
Amid media speculation that Israel may try to halt Iran's nuclear programme by carrying out air strikes on some atomic facilities in Iran, Iranian officials have said Tehran would retaliate promptly and strongly to any such attack.