U.S. Reps. Michael McCaul (R-TX) and Brian Fitzpatrick (R-PA) helped lead more than 385 congressional members in urging increased diplomatic action by the United States to renew the expiring United Nations arms embargo against Iran, as well as U.N. travel restrictions on Iranian individuals involved with dangerous proliferation activities.

“Nearly every member of the U.S. House of Representatives is in agreement: Iran must not be allowed to buy or sell weapons,” Rep. McCaul said on Monday. “I am proud the House is speaking with one voice to protect the world against Iran’s aggressive and destabilizing behavior.”

“I am encouraged to see so many of my colleagues from both sides of the aisle add their voice in support of this critical national security matter,” added Rep. Fitzpatrick.

The U.N. arms embargo on Iran is set to expire in October, according to a May 4 letter Rep. McCaul, Rep. Fitzpatrick, and their colleagues sent to U.S. Secretary of State Mike Pompeo in which they expressed concerns that the ban’s expiration could lead to more states buying and selling weapons to and from Iran.

“Additionally, states concerned about Iran’s malign activities may feel they do not have sufficient legal authority to stop transfers once the U.N. embargo expires. This could have disastrous consequences for U.S. national security and our regional allies,” the members wrote, asking Pompeo to work with U.S. allies to extend these provisions to prevent Iran from buying and selling weapons.

The lawmakers also asked the secretary to make clear to the international community that U.S. sanctions on Iranian arms transfers remain in place and will be fully enforced, according to their letter.

“This isn’t a Republican or Democrat issue, or even just an American issue,” said Rep. McCaul, ranking member of the U.S. House Foreign Affairs Committee. “We need to extend the U.N. arms embargo on Iran for the sake of international peace and security.”

Rep. Fitzpatrick agreed, saying that Iran has repeatedly shown that it “cannot be trusted.”

For instance, U.N. Security Council Resolution 2231 bans arms transfers to and from Iran, yet Iran routinely violates the resolution with impunity, particularly in Syria, Iraq, and Yemen, according to the members’ letter, which noted that Iran’s illicit transfers of weapons directly contribute to some of the most destabilizing threats to the U.S. and its Middle East partners.

Iran’s “efforts to destabilize the region and the world will only increase if we do not extend the U.N. embargo,” Rep. Fitzpatrick said. “Iran must be prohibited from buying and selling weapons, and moreover, we must prevent Iran from increasing its influence in the region.”