A group of U.S. Republican senators on Thursday unveiled legislation that would require the Obama administration to impose stricter sanctions on every sector of Iran’s economy that supports the country’s ballistic missile program, The Associated Press (AP) reported.

The bill, introduced by Sen. Kelly Ayotte, is a reflection of longstanding exasperation among Republican lawmakers who have complained that President Barack Obama has failed to properly punish Tehran for repeatedly defying a UN ballistic missile test ban.

On October 10, Iran conducted ballistic missile test which elicited strong condemnation from members of the UN Security Council. A month later, it tested another ballistic missile, and an American official said other undeclared tests occurred earlier than that.

On March 9, Iran’s Revolutionary Guard test-fired two more ballistic missiles which American officials said were in defiance of the UN resolution, which calls for Tehran not to launch any ballistic missiles capable of delivering a nuclear weapon.

In addition to the missile test, the words “annihilate Israel” were reportedly written on the missiles, and Iranian officials claimed the missile systems being developed were needed “to confront the Zionist entity” and to ensure “its collapse”.

Ayotte and other Republicans said on Thursday that senior U.S. military officials are in favor of tougher sanctions. Both Defense Secretary Ashton Carter and Army Gen. Joseph Votel, Obama’s choice to be the next U.S. commander for the Middle East, have told the Senate Armed Services Committee in the last week that harder hitting sanctions are necessary, according to AP.

Iran’s UN Mission has claimed that the Islamic Republic “has never sought to acquire nuclear weapons and never will in the future.” It said the missile tests “were part of ongoing efforts of its armed forces to strengthen its legitimate defense capabilities … against security threats.”

The administration in January announced sanctions against Tehran for missile firings in late 2015, but Republicans called those measures tepid and weak.

Last week, House Speaker Paul Ryan said American lawmakers would continue to press for new sanctions against Iran and would continue those efforts”until the regime ends its violent, provocative behavior against the U.S. and our allies.”

Ayotte’s legislation is supported by Senate Majority Leader Mitch McConnell, which suggests the bill could be taken up quickly, noted AP. Republicans remain frustrated after they were unable to scuttle the international accord to check Iran’s nuclear program in exchange for economic sanctions relief.

“Tough words alone will not deter the world’s worst state sponsor of terrorism from continuing to develop its ballistic missile program,” Ayotte said.

The legislation requires new sanctions against persons who knowingly aid Iran’s missile program and against entities controlled or owned in part by Iran’s primary ballistic missile organizations.

The bill also would mandate a broad reach by requiring the president to issue sanctions on entire sectors of Iran’s economy found to be directly or indirectly supporting Iran’s missile program.