Cuba has accused the US of issuing far fewer visas to Cubans wanting to leave than allowed for by an agreement between the two countries.
US coastguards often pick up Cuban migrants in the Florida Straits
The Cuban foreign ministry said the US was intentionally delaying meeting the visa quota to destabilise the country.
The deal was reached in 1994, after thousands fled Cuba on makeshift rafts.
It allows Washington to grant up to 20,000 entry visas a year for Cubans. Over the past nine months, fewer than 11,000 have been issued.
"It is evident a considerable delay exists," the ministry said.
"Why would [the United States] want to make the migratory situation worse between both countries?"
The statement said the delays would result in a rise in illegal immigration.
Many Cubans try to leave the island on makeshift rafts every year.
Under a US policy that grew out of the 1994 agreement, those stopped at sea are returned to their homeland, while those who reach US shores are allowed to stay.
In the past, Washington has rejected similar accusations by Havana by stating that that the 1994 deal does not require that the full 20,000-visa quota should be met each year.