WASHINGTON (Reuters) — The U.S. government has seen proof that at least some members of the group of American and Canadian missionaries kidnapped in Haiti last month are alive, according to a senior Biden administration official.

The official, who declined to be named, did not give further details.

U.S. officials have been spearheading the efforts to safely retrieve the missionaries, who were on a trip organized by the Ohio-based Christian Aid Ministries.

The 16 Americans and one Canadian, including five children, were abducted after visiting an orphanage.

Details about the law enforcement effort have been sparse since the Oct. 16 attack. U.S. President Joe Biden is being briefed daily on the law enforcement effort, officials have said.

Liszt Quitel, Haiti’s interior minister, and Chenald Augustin, a spokesman for the office of Prime Minister Ariel Henry, did not respond to requests for comment.

A Haitian man identifying himself as the leader of the 400 Mawozo gang on YouTube said last month that he was willing to kill “these Americans” if he did not get what he needed.

The missionaries were not present in the video.

Haitian officials have said the gang is demanding a $1 million per person ransom. The 400 Mawozo began as small-time local thieves and rose to become one of Haiti’s most feared gangs, controlling a swath of territory east of the capital Port-au-Prince, according to security experts.

The incident has focused global attention on Haiti’s dire kidnapping problem, which has worsened amid economic and political crises and spiraling violence.

In July, President Jovenel Moise was assassinated and in September the prime minister dissolved the electoral council, postponing the planned November election. A new date has yet to be set.

The United States would like to see the country move toward elections but thinks more must be done to improve the security situation and internal dialogue first, the U.S. official said.