UNITED NATIONS — The U.S. has notified the United Nations that it is freezing funding to a U.N.-backed mission in Haiti tasked with fighting gangs trying to seize full control of the country’s capital, the U.N. said Tuesday.

The U.S. has been the biggest contributor to the mission led by Kenyan police, which was launched last year and is struggling with a lack of funding and personnel. The halt will have an “immediate impact” on the mission, U.N. spokesman Stephane Dujarric said.

The United States had committed $15 million to the trust fund that finances the multinational force, he said. With $1.7 million of that already spent, “$13.3 million is now frozen,” Dujarric said.

The move comes as U.S. President Donald Trump imposes a sweeping freeze on foreign assistance, leading to thousands of U.S. aid agency employees and contractors being laid off and programs worldwide shut down.

U.S. Secretary of State Marco Rubio has offered a waiver for life-saving programs, but confusion over what is exempt from stop-work orders — and fear of losing U.S. aid permanently — is still freezing aid and development work globally.

The halt in funding appeared to take officials leading the Kenyan mission by surprise. When asked for comment, mission spokesman Jack Mbaka declined to give any immediate reaction.

The announcement was made just hours after a military contingent of 70 soldiers from El Salvador arrived in Haiti, joining more than 600 Kenyan police officers already on the ground backed by police and soldiers from other countries including Jamaica and Guatemala.

It’s unclear what impact the halt in U.S. funding for the mission might have on efforts to transform it into a U.N.-peacekeeping mission.

“The international security mission in Haiti was already facing very great odds; it was already very short staffed. With this withdrawal of aid, it will make their job there even harder,” said Michael Deibert, author of “Notes From the Last Testament: The Struggle for Haiti,” and “Haiti Will Not Perish: A Recent History.”

The halt in funding comes amid a relentless attack by hundreds of gang members in an upscale neighborhood in the capital of Port-au-Prince that began more than a week ago and has left at least 40 dead.

Gangs already control 85% of the capital, and U.N. Secretary-General António Guterres recently warned they could overrun Port-au-Prince without additional support for the multinational force.

More than 5,600 people were reported killed last year across Haiti and more than 2,200 others were injured. Gang violence has left more than one million people homeless in recent years, according to the U.N.

“It’s obvious that the situation in Haiti is one of unprecedented severity,” said Diego Da Rin, an analyst with the International Crisis Group.

The U.N.’s Dujarric said the latest human rights report from the U.N. political mission in Haiti known as BINUH reiterated concerns over the continuing rape and sexual exploitation of women and girls by gang members. I also cited the recruitment of children by the gangs.

Coto reported from San Juan, Puerto Rico. Associated Press reporter Evens Sanon in Port-au-Prince contributed.

previous coverage

• USAID website goes offline in Trump administration’s 2-week-old freeze on foreign aid worldwide
• Pauses on US foreign aid and local grants send funders and nonprofits scrambling