Former Vice President Mike Pence and 107 other former world leaders on Tuesday signed a letter to President Joe Biden and his counterparts in Canada, the United Kingdom, and Europe calling on the West to adopt a tougher approach to Iran and support Iranian anti-government protesters demanding regime change.

The letter came after U.S. lawmakers last week expressed bipartisan support for the Iranian people demonstrating against their government and slammed Biden for in their view not having a coherent or comprehensive strategy toward Iran.

"We believe it is time to hold the leadership of the Islamic Republic of Iran to account for its crimes," the letter states. "We urge your nations to stand with the Iranian people in their quest for change and to take decisive steps against the current regime. This includes blacklisting the Revolutionary Guards (IRGC) and holding regime officials accountable for their crimes against humanity."

The IRGC is an Iranian military force designated by the U.S. as a terrorist organization.

Former Vice President Mike Pence

Former Vice President Mike Pence speaks to guests at the Iowa Faith and Freedom Coalition Spring Kick-Off on April 22, 2023 in Clive, Iowa.  (Scott Olson/Getty Images)

ISRAEL'S DEFENSE CHIEF WARNS TEHRAN AGAINST FURTHER NUCLEAR DEVELOPMENT: 'WE HAVE THE ABILITY TO HIT IRAN'

The letter — addressed to Biden, the prime ministers of Canada and the U.K., and heads of state across Europe — condemns Iran's "meddling" in the Middle East and Europe, noting Iran has supplied Russia with lethal drones to use in Ukraine and attempted terrorist attacks on European soil.

Experts and U.S. officials have also accused Iran of being behind a wave of attempted assassinations against American citizens on U.S. soil, including senior figures in the former Trump administration.

As for Iran's internal situation, the letter highlights how Iran notoriously executed thousands of political prisoners in 1988, when current Iranian President Ebrahim Raisi was part of a so-called "death committee" that ordered several of the killings.

The world leaders also focus on ongoing nationwide anti-government street protests in Iran. The protests erupted across Iran in September when a young woman died in the custody of Iran's so-called morality police, which had allegedly detained her for wearing a hijab, an Islamic head covering that's mandatory for women in Iran, in an "improper" way.

Protest in Iran

In this photo taken by an individual not employed by the Associated Press and obtained by the AP outside Iran, Iranians protests the death of 22-year-old Mahsa Amini after she was detained by the morality police, in Tehran, Oct. 1, 2022. (AP Photo/Middle East Images, File) (The Associated Press)

IRAN DEFIES US OVER EXECUTIONS, PUTTING THREE DEMOCRACY PROTESTERS TO DEATH

Since then, the protests have grown in scope and intensity, reaching all of Iran's 31 provinces and nearly 300 cities, according to local reports and the organized Iranian resistance movement. Chants calling for the Iranian regime's overthrow have been common at protests.

In response, the regime has violently cracked down on the demonstrations, during which hundreds of protesters have been killed and tens of thousands arrested, according to reports. Critics have also accused the regime of being involved in the recent poisoning of hundreds of school girls in the country. Iran has also increased its executions, most recently executing three protesters las week. The latter decisions triggered bipartisan outcry from U.S. lawmakers, including those on the Senate Foreign Relations Committee.

In Tuesday's letter, the world leaders call on Biden and his counterparts to stand with the protesters in their bid to topple the current regime, rejecting both the theocratic regime in power and the monarchy that preceded it.

"We encourage you to stand in solidarity with the people of Iran in their desire for a secular and democratic republic where no individual, regardless of religion or birthright, has any privilege over others," the letter states. "Through their slogans, the Iranian people have made it clear that they reject all forms of dictatorship, be it that of the deposed Shah or the current theocratic regime, and thus reject any association with either."

The leaders also express support for the National Council of Resistance of Iran, a coalition of Iranian opposition groups, and a 10-point plan for democratic transition advocated by the coalition's leader, Maryam Rajavi. 

Beyond Pence, an outspoken supporter of the Iranian opposition movement, signatories of the letter included former British Prime Minister Liz Truss, former Canadian Prime Minister Stephen Harper, and two former European Commission presidents, among dozens of other ex-heads of state.

The letter came after last week the newly formed Iranian Women Congressional Caucus held its first joint meeting with the Iran Human Rights and Democracy Caucus — both bipartisan — to express support for the Iranian protesters.

"We offer our unwavering commitment to advocating for freedom and the rights of women worldwide. This can transcend party lines and unite on issues of human rights," Rep. Nancy Mace, R-S.C., said at the event. "We must send a strong message that the international community stands in solidarity with Iranian women and will not tolerate the suppression of their rights."

President Joe Biden, right, and Iranian Supreme Leader Ali Khamenei, left

President Joe Biden, right, and Iranian Supreme Leader Ali Khamenei, left

NEW BIPARTISAN CAUCUS IN CONGRESS CONDEMNS POISONING OF IRANIAN GIRLS

The event came two days after Biden administration officials gave a classified briefing on Iran to all 100 senators. After the briefing, several senators said they were dissatisfied with what they heard about the administration's approach to Iran.

"It's been six months since President Biden declared the [Iran nuclear deal] 'dead' and we're still no closer to a more comprehensive Iran policy," Sen. Jim Risch, R-Idaho, ranking member of the Senate Foreign Relations Committee, said in a statement after the briefing. "Strategic ambiguity on Iran policy only serves to embolden the regime and push our partners closer to China. As Iran continues to illegally seize vessels, target Americans in the region, and support its terror proxies and the Russian invasion of Ukraine, Americans deserve a policy that is more than a failed nuclear negotiation."

Sen. Josh Hawley, R-Mo., expressed similar concerns when speaking to reporters immediately after the briefing.

CLICK HERE TO GET THE FOX NEWS APP

"Based on what I heard for the last 40 minutes, they [the Biden administration] don't really have much to say on the topic [of Iran]," said Hawley. "I didn't think it was a particularly useful briefing. I don't know if they really have a coherent strategy. If there is one, I didn't hear it … We didn't learn anything new or remotely classified."

The White House didn't respond to a request for comment for this story.