More than 1,000 migrants, most of them Cubans, thronged and then stormed across Panama's border into Costa Rica in a desperate bid to reach the United States, officials said.

Although all but 120 voluntarily returned to Panama hours later, the incident risked reviving a recent crisis in which thousands of Cubans determined to make it to the United States became stranded in Costa Rica because their passage north through Central America was blocked.

Television images showed migrants clashing with officials trying to stop them in Costa Rica's border town of Paso Canoas. Several car windows were broken in the scuffles.

Costa Rican officials said some Africans and Asians were among those entering and vowed to deport back to Panama any undocumented migrants, blaming Washington for "promoting" the flow of Cubans.

People leaving Communist-run Cuba are the only migrants who -- if they simply make it to US soil -- after just a medical clearance are granted temporary US residence and the right to work legally, and some health care.

Costa Rican Foreign Minister Manuel Gonzalez told a media conference that migrants were wrong to think they could push their way over the border.

"If they are trying to swamp Costa Rica by sending in avalanches of people, they are mistaken," he said. "With force, not even their little toes will enter."

Later in the day, most of the migrants had returned to Panama, Carlos Hidalgo, a spokesman for the public security ministry, told AFP.

Amid many Cubans' concerns that they may soon lose the generous US migrant benefits, the US Coast Guard has seen a spike in Cubans arriving in the United States by land and sea since Washington and Havana announced they would begin normalizing relations in December 2014.

More than 43,000 Cubans entered the United States by sea and land during fiscal year 2015 -- which ended in September -- a figure not seen for decades.

- Reinforcements to frontier -

Costa Rica said it was reinforcing security on its southern border with Panama to prevent more crossings, and deployed around 150 police officers at the flashpoint, Hidalgo said, calling the situation "under control and peaceful."

"Today, more than a thousand undocumented migrants violently and with force entered Costa Rica, which represents an affront to the Costa Rican people," the presidency said in a statement.

It stressed that the country was unable to cope with such an influx and that it had just cleared out 8,000 Cubans who had been blocked in the country when its northern neighbor Nicaragua closed its border to them five months ago.

Those stranded Cubans had been put on special flights skipping over Nicaragua, to either El Salvador or Mexico, with most of them paying their own way.

The incident deepened animosity between Nicaragua -- an ally to the Cuban government -- and Costa Rica, whose ties have been strained by border disputes.

- US policy denounced -

The statement from Costa Rica's presidency denounced US policy dating back to the Cold War many describe as "wet foot, dry foot." The US authorities repatriate Cubans picked up at sea in the shark-infested Florida Straits, but any who arrive on American shores get to stay.

It said the policy promotes such irregular migratory flows by providing "a perverse incitement" for Cubans to try to get to the United States no matter the obstacles.

The US approach, it said, "fosters conditions for human trafficking."

In the joint governmental media conference with other ministers, the head of Costa Rica's migration agency, Kattia Rodriguez, said up to 1,200 migrants may have crossed on Wednesday.

"They are mainly Cuban people," she said, with a small number of migrants from Africa and Asia.

The incident presented a new challenge to Costa Rica, which on Tuesday had hosted a meeting of Latin American and US migration officials and urged them to come up with a coordinated response on handling Cuban and African migrants.

Costa Rica stressed in the meeting that it was not permitting the entry of US-bound Cubans, 2,000 of whom had arrived in Panama in recent weeks.
Source: AFP