The Trump administration is ramping up pressure on the U.N. Security Council to extend a 13-years-old arms embargo on Iran due to expire in October -- and threatening to take “all legally available options” to extend it if China or Russia vetoes such a move.

The U.S. on Wednesday called a closed-door Security Council meeting under the so-called 2231 format -- in reference to U.N. Security Council Resolution 2231, which enshrined the 2015 Iran nuclear deal.

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The informal meeting was called to discuss an April 22 launch of a military satellite into orbit by Tehran. Officials used the meeting to highlight what it called the "ongoing violation" of the embargo by the Iranians -- violations that include funneling weapons to militant proxies in the region.

“The launch represents yet another example of Iran's relentless defiance of U.N. Security Council Resolution 2231, which calls on the regime not to undertake any activity related to ballistic missiles designed to be capable of delivering nuclear weapons – including launches using ballistic missile technology,” the mission said in a statement.

Under the Iran deal, known formally as the Joint Comprehensive Plan of Action (JCPoA), the arms embargo is due to expire in October as one of a series of restrictions that are allowed to expire. But the U.S., which has opposed easing the pressure on Iran, is urging fellow Security Council members to extend it.

“Iran’s continued violations of the Security Council’s arms embargo demands greater pressure from the Security Council, not less, and the United States will work tirelessly with a coalition of concerned nations to ensure the embargo is extended,” the statement said.

The U.S. withdrew from the Iran deal in 2018 amid concerns from the Trump administration that the deal was insufficient and allowed Iran to continue its destabilizing activities in the region. In withdrawing, the U.S. has engaged in a “maximum pressure” campaign which has involved reintroducing sanctions on Iran’s economy and top officials.

It has pointed to activities by the Iranian regime such as increased missile launches and its backing of militant terrorist proxies in places such as Iraq, Syria, Yemen and Lebanon as proof that Iran has not stopped its nefarious activities in the region.

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Now, in seeking to extend sanctions using the mechanisms of the Iran deal, the U.S. has argued that it, even though it pulled out of the deal, it is still part of resolution 2231 -- which includes a mechanism that allows an individual member to “snapback” sanctions, of which the arms embargo is one.

“U.N. Security Council resolution 2231 is pretty clear,” Pompeo told "Fox News @ Night" last month.” “That's pretty clear about what a participant is. It's separate from the JCPoA [the Joint Comprehensive Plan of Action, or Iran deal]. We are one of the participants and the participants have the right to invoke snapback in a way that will prevent this expiration of the arms sales.”

It’s a move that has got under the skin of top Iranian officials. Iranian Foreign Minister Javad Zarif sent a series of tweets blasting the U.S. argument -- accusing Pompeo of not having read the resolution, which he says includes the JCPoA.

“[Pompeo] pretends UNSCR 2231 is independent from #JCPOA. He should READ 2231,” he tweeted. “JCPOA is PART of 2231. That's why it's 104 pages—& why he’s not read it. “

On Wednesday, U.S. Special Representative for Iran Brian Hook, in an op-ed for The Wall Street Journal, reiterated that the Council “must pass a resolution to extend the arms embargo” and urged it to reject “extortion” from Tehran.

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He made it clear that the U.S. will attempt to get the arms embargo through the Security Council, writing that a resolution has been drafted and the U.S. is trying to get it passed. However, such an effort could easily get shot down by a veto by either Russia or China -- who both wield veto power in the chamber.

“If this effort is defeated by a veto, the Trump administration is prepared to exercise all legally available options to extend the embargo,” he said, referring to the “snapback” mechanism in resolution 2231.

Fox News' Ben Evansky contributed to this report.