Haiti’s prime minister, who has come under growing pressure to resign as gangs have overrun the country, said late Monday that he would step down once a transitional council had been established, to pave the way for the election of a new president and help restore stability.

“The government that I lead will withdraw immediately after the installation of this council,” Prime Minister Ariel Henry said in a speech posted on social media. Referring to the chaos in Haiti, he said, “It hurts us and it revolts us to see all these people dying. The government that I lead cannot remain insensitive to this situation.”

But it was far from clear when Mr. Henry, who had been under growing pressure to step down both in Haiti and abroad, would actually do so.

Leaders from Caribbean nations, who have led the push to create a transitional council, met for discussions in Jamaica on Monday but said no plan had been finalized. Guyana’s president, Mohamed Irfaan Ali, who leads Caricom, a union of 15 Caribbean countries, said that “we still have a long way to go.”

Secretary of State Antony J. Blinken, who attended the meeting in Kingston, Jamaica’s capital, announced that the United States would provide an additional $100 million in aid toward a United Nations-backed multinational security mission planned to deploy to Haiti. He also pledged an additional $33 million in humanitarian aid, bringing the U.S. commitments to $333 million.

“We can help. We can help restore a foundation of security,” Mr. Blinken said. “Only the Haitian people can, and only the Haitian people should determine their own future, not anyone else.”