Vice President Biden warned Wednesday that the United States would not hesitate to act against any “conventional” military activity by Iran outside of last year’s landmark nuclear deal, underscoring the Obama administration’s concern after apparent back-to-back missile tests by Tehran.

The remarks by Biden, on a visit to reassure Israeli allies strongly opposed to last year’s nuclear pact, came as Iran’s Revolutionary Guard Corps reported the test firings of two ballistic missiles capable of reaching ­Israel.

Similar Iranian tests reported Tuesday brought threats of further sanctions by the United States, which in January announced punitive measures against Iran in the wake of missile tests last year.

Iranian state television broadcast video on Wednesday purporting to show the test firings of the missiles, which the Revolutionary Guard said were part of an arsenal capable of hitting Israeli targets.

The tests signaled a show of strength by Iran’s military and appeared timed to coincide with Biden’s trip. They also followed stunning gains in last month’s parliamentary elections by Iranian moderates who back President Hassan Rouhani and support the nuclear deal, which was criticized by hard-liners, including members of the Revolutionary Guard. The deal was formally implemented in January.

Biden said Wednesday that the United States “will act” if Iran violates the nuclear pact. He also said that all Iranian programs outside the scope of the accord will be closely monitored.

“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 told reporters.

He reiterated that “a nuclear-armed Iran is an absolutely unacceptable threat to Israel, the region and the United States.”

Analysts said the missile tests appear to be an attempt by the hard-liners to assert their continued relevance after the election setbacks.

“They’re not doing particularly well,” said Trita Parsi, president of the National Iranian American Council, who is writing a book on the nuclear talks. “When you get this type of repudiation from the Iranian public, and you’re sensing that the perception of power is starting to shift, you want to make marks of this kind.”

Mike Eisenstadt, a military analyst at the Washington Institute for Near East Policy, said it may be difficult to prove that the Iranians “designed” the missiles to be nuclear-capable, which is barred by U.N. Security Council resolutions. The missiles, he said, play on the deepest fears among Iran’s foes about its nuclear intentions.

“On a certain subliminal level, people see missiles and think nukes,” Eisenstadt said. “They’re able to claim they are sticking to their nuclear obligations. But the missiles enable them to intimidate their enemies by implying they have an option in the long run to develop nuclear weapons.”

Iran’s semiofficial Fars News Agency reported that the missiles tested Wednesday were stamped with a message in Hebrew: “Israel must be wiped out.” However, there was no confirmation of the report, and no such markings were seen in state-
issued photos and video.

Missile development is not specifically prohibited under the nuclear deal, which severely limits Tehran’s uranium-enrichment and other programs to block a potential pathway to nuclear weapons. In exchange, most international sanctions on Iran were lifted.

Iran claims it has a right to develop conventional weapons and insists that the missiles are not designed to carry nuclear warheads. But the West and its allies view the reported tests as highly provocative.

In Washington, White House press secretary Josh Earnest said the United States and its allies would “redouble” efforts to limit further expansion of Iran’s missile program, but he offered no specifics.

“There is no need to doubt that the United States has Israel’s back,” Biden said after meetings with Israeli Prime Minister Benjamin Netanyahu. “This is a commitment that goes deeper than security.”

As the Iran issue loomed large, months of Israeli-Palestinian violence showed no signs of easing. On Tuesday, a Palestinian went on a stabbing rampage less than a mile from where Biden spoke at a peace center in the Mediterranean port of Jaffa. An American tourist — a graduate student from Vanderbilt University — was killed and several others were wounded, officials said. The incident followed three other attacks across Israel. At least 14 Israelis were wounded, some seriously, in the attacks. All four assailants were killed.

Netanyahu had accused Palestinian Authority President Mahmoud Abbas of not condemning the attacks.

On Tuesday, Abbas’s Fatah party posted a drawing on its Twitter account of a hand holding a knife over a map of Israel and the Palestinian territories. It described one of the Palestinian assailants as a “hero” and “martyr.”

“The United States condemns these acts,” Biden said Wednesday, “and condemns the failure to condemn these acts.”

Biden traveled to Ramallah in the West Bank in the evening to meet with Abbas in the presidential compound. The two men briefly embraced, then went upstairs to talk privately. Neither made any public remarks.

Before his trip to the West Bank, Biden and several family members made an unannounced stop in Jerusalem’s Old City. They entered through the Jaffa Gate — the scene of some recent attacks against Israeli soldiers and civilians — and visited the Church of the Holy Sepulchre, a major pilgrimage site built upon the location where tradition says Jesus was crucified and which holds his empty tomb.

Biden was accompanied by three of his grandchildren and daughter-in-law Hallie Olivere Biden. She was married to Biden’s son Beau, who died of brain cancer last year.

Morello reported from Washington. Brian Murphy, also in Washington, contributed to this report.

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