PORT-AU-PRINCE, Haiti — American officials are working with Haitian authorities to try to secure the release of 12 adults and five children connected with a U.S.-based missionary group who were abducted over the weekend by a gang notorious for killings, kidnappings, and extortion.

Police say the group was snatched Saturday by the 400 Mawozo gang in the community of Ganthier, which lies within the gang’s territory in the Croix-des-Bouquets area east of the capital of Port-au-Prince.

As authorities sought the release of the 16 Americans and one Canadian from the Ohio-based Christian Aid Ministries, local unions and other organizations launched a strike Monday to protest Haiti’s worsening security. The streets of Port-au-Prince and other cities were largely empty as public transportation drivers stayed home. Businesses and schools also closed to join the strike.

“The population cannot take it anymore,” said Holin Alexis, a moto-taxi driver who joined the strike.

Barricades of burning tires closed off some streets in the capital and in other cities, including Les Cayes in southern Haiti, with some people throwing rocks at the occasional car that drove past.

Only a handful of moto-taxi drivers like Marc Saint-Pierre zoomed through Port-au-Prince looking for customers. He said he was attacked for working on Monday but had no choice.

“I have children, and I have to bring food to my house today.”

Gang Kidnappings Spike in Haiti

The Western Hemisphere’s poorest nation is again struggling with a spike in gang-related kidnappings that had diminished in recent months, after President Jovenel Moïse was fatally shot at his private residence on July 7 and a magnitude 7.2 earthquake killed more than 2,200 people in August.

“Everyone is concerned. They’re kidnapping from all social classes,” Méhu Changeux, president of Haiti’s Association of Owners and Drivers, told Magik9 radio station.

He said the work stoppage would continue until the government could guarantee people’s safety.

The kidnapping of the missionaries came just days after high-level U.S. officials visited Haiti and promised more resources for Haiti’s National Police, including another $15 million to help reduce gang violence, which this year has displaced thousands of Haitians who now live in temporary shelters in increasingly unhygienic conditions.

The U.S. State Department said Sunday that it was in regular contact with senior Haitian authorities and would continue to work with them and interagency partners.

“The welfare and safety of U.S. citizens abroad is one of the highest priorities of the Department of State,” the agency said in a statement.

Youngest Kidnap Victim Is 2 Years Old

Christian Aid Ministries said the kidnapped group included seven women, five men and five children, including a 2-year-old. The organization said they were taken while on a trip to visit an orphanage. A sign on the door at the organization’s headquarters in Berlin, Ohio — the center of Amish tourism — said it was closed due to the kidnapping situation.

“Join us in praying for those who are being held hostage, the kidnappers and the families, friends and churches of those affected,” Christian Aid Ministries said in a statement. “As an organization, we commit this situation to God and trust him to see us through.”

An annual report issued last year by Christian Aid Ministries said its American staffers had returned to their base in Haiti after a nine-month absence “due to political unrest” and noted the “uncertainty and difficulties” that arise from such instability.

Nearly a year ago, Haitian police issued a wanted poster for the alleged leader of the 400 Mawozo gang, Wilson Joseph, on charges including murder, attempted murder, kidnapping, auto theft, and the hijacking of trucks carrying goods. He goes by the nickname “Lanmò Sanjou,” which means “death doesn’t know which day it’s coming.”