State Department officials admitted Tuesday that the Obama administration has not demanded that Central American countries end their efforts to airlift Cuban immigrants to the southern U.S. border.

"We have not told them not to do the airlift," Francisco Palmieri, a senior official in the Bureau of Western Hemisphere, testified at a hearing under questioning from Sen. Marco Rubio, R-Fla.

Costa Rica and Panama have flown about 8,000 Cuban migrants to northern Mexico, part of an "upsurge" in migration that has brought about 18,500 Cubans to the Texas-Laredo Border Patrol field office over a five-month period. While the U.S. hasn't demanded an end to this, Palmieri told Rubio that the Central American countries need to enforce their own immigration laws.

Palmieri said that "there is talk of another airlift" from Panama, even though Costa Rica has pledged to lock down its borders.

"The engagement with the countries focuses on encouraging them to ensure safe legal and orderly migration," he said. "We continue to urge the countries to enforce their migration laws, to strengthen their border controls, and to address undocumented and irregular migration by returning people to their last point of origin."

Rubio said the United States has "significant potential leverage with these countries," and asked repeatedly if the State Department has instructed the countries not to airlift the migrants to the southern border.

"The minute the word gets out that if you can get into this country they're going to put you on a plane and fly you close to the U.S. border so you can get in, you're encouraging more people to do this," said Rubio, who chairs the Foreign Relations subcommittee on the western hemisphere.

Rubio believes that Cuban immigrants are taking advantage of U.S. government policies that have been in place for decades throughout the standoff with the Fidel Castro's regime, but that might be obsolete now that the President Obama has normalized diplomatic relations with the island country. He tried to force a vote on legislation last week that would end the special refugee status for Cubans, but was stymied.

"A significant number of people are drawn to this country from Cuba because they know when they arrive they can step foot on dry land, they will immediately receive status and they immediately qualify for a package of federal benefits that no other immigrant group would qualify for unless they can prove they're refugees," he said recently on the Senate floor. "This current policy is not just being abused, it's hurting the American taxpayers."