Mexican authorities said they were carrying out search-and-rescue operations for nine people on two sailboats that disappeared while carrying humanitarian aid to Cuba.

In a statement, the Mexican Navy said the boats were last seen leaving Isla Mujeres off Mexico’s Caribbean coast.

The boats, which were loaded with humanitarian supplies — rice, beans, baby formula, and medicine — were expected to arrive in Havana either Tuesday or Wednesday. Another boat from the same convoy arrived on Tuesday.

The vessels are part of a grassroots effort to provide aid to energy-poor Cuba, which has been subject to food shortages and power outages after the U.S. tightened its economic embargo on the country.

Reports said the nine individuals on board were of different nationalities.