Mexico’s navy said on Thursday it had activated a search-and-rescue operation in the ​Caribbean to locate two sailboats carrying humanitarian aid to Cuba ‌after the vessels failed to arrive in Havana as scheduled.

In a statement, the navy said the two boats left Isla Mujeres, in the Mexican Caribbean state ​of Quintana Roo, last week bound for Havana with nine ​crew members of different nationalities on board.

The vessels had ⁠been expected to arrive between March 24 and 25, but there ​had been no communication from them and no confirmation of their arrival, ​the navy said.

The two missing boats are part of a broader grassroots aid effort for energy-strapped Cuba, which has been suffering prolonged power outages and a ​deepening economic crisis after the US tightened an embargo on oil and ​other goods.

A separate vessel from the convoy arrived in Havana on Tuesday.

Volunteers in Mexico ‌last ⁠week loaded boats with rice, baby wipes, beans, baby formula, medicine and other supplies as part of the “Nuestra America Convoy,” a non-government initiative seeking to deliver food, medicines and energy-related goods to the island.

“The captains ​and crews are ​experienced sailors, and ⁠both vessels are equipped with appropriate safety systems and signalling equipment,” a spokesperson for the convoy said ​in a statement to Reuters.

“We are cooperating fully with ​the authorities ⁠and remain confident in the crews’ ability to reach Havana safely.”

Mexico also established contact with maritime rescue coordination centres in Poland, France, Cuba ⁠and the ​United States, as well as diplomatic ​representatives of the countries of origin of those on board, the navy said.