Mexican authorities rescued 15 Cubans traveling in a rickety boat off the coast of the resort city of Cancun, the Navy said on Thursday.

The travelers were discovered by fishermen and handed over to migration authorities.

Cuba and the United States said Tuesday they had wrapped up a third round of talks on normalizing relations, but gave few details beyond praising the "constructive" environment.

Monday's closed-door talks between Roberta Jacobson, the top U.S. diplomat for Latin America, and Josefina Vidal, Cuba's top diplomat for U.S. affairs, focused on "reestablishing diplomatic relations and reopening embassies," a State Department spokesperson said.

Cuba's Fidel Castro warned Tuesday that Venezuela was prepared to confront U.S. "threats and impositions," and said Washington could no longer count on the Venezuelan military to do its bidding.

Venezuela "will never allow a return to the shameful pre-revolutionary past," Castro said in a letter to Venezuela's President Nicolas Maduro published in Cuba's state-run media.

U.S. and Cuban officials met Monday in Havana for new talks on restoring diplomatic ties, but their historic rapprochement was marred by tensions over Venezuela.

The top U.S. diplomat for Latin America, Roberta Jacobson, met her Cuban counterpart Josefina Vidal behind closed doors for a third round of talks on normalizing relations, but the atmosphere of reconciliation was marred by protests over Washington's treatment of Venezuela.

EU foreign policy chief Federica Mogherini is to visit Cuba later this month in a bid to spur talks aimed at normalizing ties with the Communist-led island state, the first such trip by a top EU diplomat.

The planned visit appears to mark a further thaw in relations between Cuba and the West, especially after the dramatic rapprochement between Havana and Washington in the last few months.

American and Cuban diplomats will hold the next round of talks on restoring diplomatic ties and reopening their embassies in Havana on Monday, the State Department announced.

Top U.S. diplomat for Latin American, Roberta Jacobson, will return on March 15 to the Cuban capital for a third round of negotiations, the department said in a statement.

Cuba rallied behind Venezuela on Tuesday, offering its closest ally "unconditional support" after U.S. President Barack Obama authorized new sanctions against officials of the turbulent South American oil producer.

The Cuban reaction marked its first public confrontation with the United States since the two countries began discussions in December on fully restoring diplomatic relations.

The European Union and Cuba held a third round of "frank" talks Wednesday aimed at normalizing relations, as Havana and Washington work through their own historic rapprochement.

The two-day session in Havana, part of a dialogue that began 11 months ago, is aimed at tackling sensitive human rights issues and finalizing an agreement "on political dialogue and cooperation," meant to turn the page on a decade of estrangement.

The comments by China's foreign ministry came one day after Colombian authorities announced that they had detained the captain of the Hong Kong-registered Da Dan Xia and would charge him with weapons trafficking.

The general cargo ship, which has been held since Saturday, was loaded with undeclared military equipment including about 100 tonnes of gunpowder, 99 projectile bases and 3,000 artillery cartridge cases, a prosecutor's office spokesman told reporters in Bogota.

President Francois Hollande will visit Cuba on May 11 in the first ever such visit by a French head of state, the French presidency announced Tuesday.

The trip is also set to be the first by a Western leader since the United States and Cuba announced their historic rapprochement on December 17.