Thousands of Cubans backed up in Costa Rica and Panama in a frustrated bid to reach the United States will not be permitted to transit through Guatemala, Costa Rica's foreign minister said Thursday.

The Guatemalan government has rejected that proposal, Manuel Gonzalez said, dealing another blow to Costa Rica's advocacy of a Central American "humanitarian corridor."

U.S. and Cuban diplomats met Monday on implementing their migration agreements and cooperating to discourage migrant trafficking, but reached no new accord, Cuban officials said.

The high-level discussion was about implementing agreements already in effect such as those on visas for Cubans wanting to emigrate, visitors' visas and both sides working to discourage illegal emigration and people trafficking, a Cuban embassy statement said.

Hundreds of furious Cubans chanting and brandishing air tickets protested Friday outside Ecuador's embassy in Havana over new visa restrictions designed to stop Cuban migrants traveling through the region to the United States.

It comes with 3,000 Cubans languishing at Costa Rica's border with Nicaragua after that country closed its border to them, triggering a regional crisis over what to do with desperate Cubans traveling through South and Central America in the hopes of making it to the U.S.

Cuban migrants aiming for a new life in the U.S. but stranded in Costa Rica by a Nicaragua border firmly closed to them expressed mounting anger and desperation on Thursday.

Some of the 3,000 Cubans stymied on the border voiced frustration at the lack of a diplomatic solution for their plight, and a sense of betrayal by Nicaragua, a Cuban ally, over the decision it took two weeks ago to shut them out.

A protest by desperate Cuban migrants stranded on their journey to the United States paralyzed a key border crossing between Costa Rica and Nicaragua Tuesday.

Long lines of buses and trucks formed on both sides of the Central American border as the migrants refused to let traffic pass, authorities from the two countries said.

A surge of some 2,000 Cuban migrants trying to cross Central America to reach the United States triggered a diplomatic spat between Costa Rica and Nicaragua Monday, plunging tense relations between the two countries to a new low.

The row boiled over this past weekend when Nicaragua forcibly sent back the Cubans, who had been given temporary visas by Costa Rica to traverse its territory, ignoring an appeal by San Jose that they be given a "humanitarian corridor" through the region.

A Chinese naval flotilla arrived in Cuba Tuesday to bolster close military ties between the two Communist-ruled allies, its commander Wang Jianxun said.

"This is the first time a (Chinese) military flotilla has come to the island," Wang said at the Port of Havana.

Former Cold War foes the United States and Cuba began talks on how to cooperate in fighting trafficking and organized crime on Monday as they slowly normalize ties.

The neighbors across the Florida Straits renewed their diplomatic relations in July after a 50-year standoff, but the latest talks were the first on law enforcement.

The United States and Cuba have agreed on the need to cooperate on security issues surrounding trade and travel between the two former Cold War foes, the communist party newspaper Granma said Thursday.

U.S. Deputy Secretary of Homeland Security Alejandro Mayorkas held talks Wednesday with Cuba's recently named Interior Minister Major General Carlos Fernandez Gondin, the latest in a series contacts since the two countries restored diplomatic relations in July.

Visiting Irish republican leader Gerry Adams told Cuban leaders that he would like to see closer ties between the Caribbean nation and his country, state media here said Thursday.

Adams told Ana Maria Machado, the vice president of Cuba's legislature, that in Ireland there was plenty of solidarity with the Cuban people, the AIN news agency reported.