Ebrahim Raisi takes the world stage as antigovernment protests rock Iran.

President Ebrahim Raisi of Iran will make his debut on the world stage at the United Nations General Assembly on Wednesday as his country is rocked by antigovernment protests triggered by the death of a young woman in police custody.

Before departing Iran for New York on Monday, Mr. Raisi, a hard-line cleric, told local news media, “I will be the voice of the Iranian people at the United Nations.”

But on Tuesday in cities across Iran, protesters, led by women, were calling for an end to the Islamic Republic, and many women were taking off their mandatory head scarves, waving them in the air, tearing them up and setting them on fire, according to eyewitnesses, news reports and videos posted on social media. At least five people have been killed, according a human rights group.

The protests were in response to the death on Friday of Mahsa Amini, 22. Her family says that she was beaten and suffered a head injury while she was held by the morality police, which had arrested her on charges of violating Iran’s hijab law, which requires women to cover their hair and wear loosefitting robes. The authorities deny that assertion and Mr. Raisi has ordered an investigation.

“The situation in Iran will bring shame and embarrassment to Mr. Raisi as he makes his first appearance on the world stage,” said Ali Akbar Mousavi Khoeini, a former Iranian lawmaker from the reformist faction who is now a human-rights activist in Maryland.

Ahead of the U.N. gathering, where Mr. Raisi will give a speech, U.S. officials and European diplomats had said that they planned to use the platform and meetings to pressure Iran to revive the 2015 nuclear deal.

President Emmanuel Macron of France, who met Mr. Raisi on Tuesday, told BBC’s Persian news service that the two had a long talk about the nuclear deal, but Mr. Macron had made it “very clear that we were very supportive of human rights and especially women’s rights,” and that “the credibility of Iran is now at stake regarding the fact that they have to address this issue.”

Mr. Raisi’s ascent to the presidency in 2021 was contentious at home and abroad. The elections were widely viewed as engineered by disqualifying his serious rivals to guarantee his win for the conservatives in order to consolidate power.

Mr. Raisi is accused by Amnesty International and Human Rights Watch for crimes against humanity for his role in the execution of 5,000 political prisoners in the 1980s. Mr. Raisi was part of committee that screened prisoners and gave — without due judicial process — execution orders. He has defended the killings as justified and not denied his role in the committee.

Several Iranian exiled opposition groups — who range from pro-democracy activists to monarchists to Mujahedeen Khalq, or M.E.K., an insurgent group formerly designated by the United States and Europe as a terrorist organization — have planned protests outside the United Nations in New York City on Wednesday. Joining the demonstrators will be Ebrahim Hamedi, the Iranian singer known as Ebi who lives in Los Angeles.