Negotiations stretched into a fourth day seeking the return of 17 members of a U.S.-based missionary group kidnapped over the weekend by a violent gang that is demanding $1 million ransom per person.

The group includes five children whose ages range from 8 months to 15 years, although authorities were not clear whether the ransom amount included them, a top Haitian official said Tuesday. Sixteen of the abductees are Americans and one Canadian.

The abduction is one of at least 119 kidnappings recorded in Haiti for the first half of October, according to the Center of Analysis and Research of Human Rights, a local nonprofit group. It said a Haitian driver was abducted along with the missionaries, bringing the total to 18 people taken by the gang.

The Haitian official, who was not authorized to speak to the press, told The Associated Press that someone from the 400 Mawozo gang made the ransom demand Saturday in a call to a leader of the Ohio-based Christian Aid Ministries shortly after the abduction.

“This group of workers has been committed to minister throughout poverty-stricken Haiti,” the Ohio group said, adding that the missionaries worked most recently on a project to help rebuild homes lost in a magnitude-7.2 earthquake that struck southwestern Haiti on Aug. 14.

The group was returning from visiting an orphanage when it was abducted, the organization said.

READ: Haiti gang seeks $17M for kidnapped US missionaries

Responding to the recent wave of kidnappings, workers staged a protest strike that shuttered businesses, schools and public transportation starting Monday. The work stoppage was a new blow to Haiti’s anemic economy. Unions and other groups vowed to continue the shutdown indefinitely.

In a peaceful demonstration Tuesday north of Port-au-Prince, dozens of people walked through the streets of Titanyen demanding the release of the missionaries. Some carried signs that read “Free the Americans” and “No to Kidnapping!” and explained that the missionaries helped pay bills and build roads and schools.

“They do a lot for us,” said Beatrice Jean.

Meanwhile, the country’s fuel shortage worsened, with businesses blaming gangs for blocking roads and gas distribution terminals.

Hundreds of motorcycles zoomed through the streets of Port-au-Prince on Tuesday as the drivers yelled, “If there’s no fuel, we’re going to burn it all down!”

One protest took place near the prime minister’s residence, where police fired tear gas to disperse a crowd demanding fuel.

In Washington, White House press secretary Jen Psaki said Tuesday that the FBI was “part of a coordinated U.S. government effort” to free the missionaries. The U.S. Embassy in Port-au-Prince was coordinating with local officials and the hostages’ families.

“We know these groups target U.S. citizens who they assume have the resources and finances to pay ransoms, even if that is not the case,” Psaki said, noting that the government has urged U.S. citizens not to visit Haiti.

It is longstanding U.S. policy not to negotiate with hostage takers, and Psaki declined to discuss details of the operation.

The kidnapping was the largest of its kind reported in recent years. Haitian gangs have grown more brazen as the country tries to recover from the July 7 assassination of President Jovenel Moïse and the earthquake that killed more than 2,200 people.

Christian Aid Ministries said the kidnapped group included six women, six men and five children. A sign on the door at the organization’s headquarters in Berlin, Ohio, said it was closed due to the kidnapping situation.

News of the kidnappings spread swiftly in and around Holmes County, Ohio, hub of one of the largest populations of Amish and conservative Mennonites in the United States, said Marcus Yoder, executive director of the Amish & Mennonite Heritage Center in nearby Millersburg, Ohio.

Christian Aid Ministries is supported by conservative Mennonite, Amish and related groups that are part of the Anabaptist tradition.

READ: Protest strike shuts down Haiti amid search for missionaries

The organization was founded in the early 1980s and began working in Haiti later that decade, said Steven Nolt, professor of history and Anabaptist studies at Elizabethtown College in Pennsylvania. The group has year-round mission staff in Haiti and several countries, he said, and it ships religious, school and medical supplies throughout the world.