A series of trips to Cuba by U.S. lawmakers is in doubt amid questions over the communist government's eagerness or ability to accommodate a surge of new interest and possible investment from the United States. 

American officials said the Cuban government has pushed off all congressional visits, including one by House Minority Leader Nancy Pelosi, until at least mid-April. The Cuban Interests Section in Washington said some will go forward in the coming days, but others are postponed. 

Several members of Congress had planned to go to the island country this month. They included Pelosi, a California Democrat, and Sen. Jeff Flake, an Arizona Republican, who has proposed ending the U.S. travel embargo of Cuba. 

President Raul Castro's government has been scrambling to adjust to the possibility of new U.S. travel and investment in Cuba since he and President Barack Obama announced in December that the two countries would repair ties after a half-century of enmity. 

And in a surprise development, Obama administration officials said they were informed by their Cuban counterparts earlier this week that no congressional visits would be allowed to travel to Cuba until April 15. They spoke on condition anonymity because they were not authorized to speak on the record. 

The Cuban Interests Section in Washington rejected that account, saying some delegations would be arriving in the next days. Pelosi's office had no immediate comment. 

A Cuban government spokesman, who demanded anonymity because he wasn't authorized to talk publicly, said Cuba is receiving a large number of requests for visits. As a result, he said, the government is "arranging for the best possible dates for their visits so they get the attention they deserve in the middle of the many tasks we are facing at this moment in Cuba." 

Many of the trips aim to explore new business opportunities as part of the thaw in U.S.-Cuban tensions. The administration last month significantly eased the 54-year economic embargo of Cuba, allowing U.S. telecommunications exports for the first time and ending a restriction on American credit and debit card transactions on the island. 

Cubans are still trying to gauge the potential effects of the changes. U.S. companies also are still trying to make sense of the new regulations and much remains unclear. Only Congress has the power to fully lift the embargo, a step Obama is calling for but Republican leaders in the House and Senate oppose. 

The most immediate objective of U.S.-Cuban diplomacy right now is re-establishing embassies. 

The U.S. had been seeking to clinch an agreement before the Summit of the Americas in Panama. The meeting of Western Hemisphere nations takes place April 10-11 and could bring Obama and Castro together for a face-to-face meeting. 

But the U.S. says Cuba must first end restrictions on American diplomats, shipments to the current U.S. Interests Section in Havana and entrance by Cubans to that building for embassies to be restored. 

Cuba's most pressing demand is an end to banking restrictions, many of which are linked to its U.S. designation as a "state sponsor of terrorism." The Obama administration is likely to lift Cuba from that list in the next months.