Iran test fired two ballistic missiles on Wednesday with the words "Israel must be wiped out" written on their sides in the latest of a series of provocative moves by the country's hardliners.
The two Qadr-H missiles had the words written in Hebrew as they were fired from a mountain range in northern Iran, according to the semi-official Fars news agency.
"The 2,000-kilometer range of our missiles is to confront the Zionist regime," said Brigadier General Amir Ali Hajizadeh of Iran's Revolutionary Guard. "Israel is surrounded by Islamic countries and it will not last long in a war. It will collapse even before being hit by these missiles."
More missiles were tested on Tuesday in what Iran described as a show of its "deterrent power".
The launches would be provocative at any time but are particularly notable given that Joe Biden, the US vice president, is in Israel on an official visit. Speaking after the tests and amid a wave of Palestinian violence, Mr Biden vowed that Israelis "never need to doubt that the United States of America has Israel’s back".
The US said the missile launches appeared to be a violation of UN Security Council resolution 2231, which forbids Iran from testing missiles which could be used to carry nuclear warheads.
However, the US does not see the tests as a violation of the nuclear agreement reached between Iran and six world powers last summer.
"It is inconsistent with 2231; it’s not a violation of the Iran deal itself," said John Kirby, a spokesman for the US State Department.
The US could seek fresh UN sanctions in response to the tests even as it moves ahead with the implementation of the nuclear agreement.
Mr Biden said the US "will act" if it finds evidence that Iran broke the terms of the nuclear agreement and was closely monitoring its activities outside the scope of the deal. "All their conventional activity outside the deal, which is still beyond the deal, we will and are attempting to act wherever we can find it," he said.
Iran says the missiles are not designed to carry nuclear warheads and therefore it is not in violation of the UN resolution.
The missile tests were carried out by Iran's Revolutionary Guard, which reports directly to Iran's supreme leader, Ayatollah Ali Khamenei, rather than the government of President Hassan Rouhani.
The testing exercise was dubbed “The Power of Velayat”, a reference to Iran's dominant theory of political Islam.
The Guard are a major force within Iranian politics and opposed to Mr Rouhani's efforts to bring his country in from the diplomatic cold.
The missile tests are seen as a way for the Guard to flex its muscles, especially after hardliners lost ground to Mr Rouhani's relatively moderate allies in last month's elections.
Despite the breakthrough at the nuclear talks, the US and Iran have clashed on several fronts.
Earlier this year, Iran captured US Navy sailors who accidentally steered into Iranian waters. An Iranian drone was flown over a US aircraft carrier in the Persian Gulf. Iran also continues to support the regime of Bashar al-Assad in Syria.
General Lloyd Austin, commander of US forces in the Middle East, said that the nuclear agreement had not brought an end to Iranian provocations.
"There are a number of things that lead me to personally believe that, you know, their behavior is not — they haven't changed any course yet," he told a Senate hearing on Tuesday.