Ramon Espinosa, Associated Press
Magnets for sale decorate a tourist shop, one showing an image of U.S. President Barack Obama smelling a cigar, at a market in Havana, Cuba, Monday, March 16, 2015. U.S. and Cuban officials are meeting Monday in last-minute closed door negotiations in Havana, in hopes of restoring full diplomatic relations before the Summit of the Americas in April. The magnet in the bottom row, second from left, reads in Spanish: "Here, nobody gives up," a popular quote attributed to Cuba's late revolutionary hero Camilo Cienfuegos.

HAVANA — U.S. and Cuban diplomats talked behind closed doors Monday in a last-minute round of negotiations aimed at restoring full diplomatic relations before a key regional summit in less than a month.

A small team of negotiators led by Assistant Secretary of State for Western Hemisphere Affairs Roberta S. Jacobson met with Josefina Vidal, Cuba's top diplomat for U.S. affairs, in open-ended talks announced less than 48 hours before Jacobson flew to Havana on Sunday.

The U.S. and Cuba held their first round of talks in Havana in January, a little more than a month after presidents Barack Obama and Raul Castro announced that they would reopen embassies in each other's countries and try to move toward a broader normalization.

The second round was held in Washington last month and both sides said they were optimistic that they would be able to resolve a series of sticking points before Obama and Castro attend the Summit of the Americas in Panama on April 10-11.

The first rounds each lasted a day and saw negotiators routinely issuing updates on progress. This week's was held without a finishing date or any scheduled statements to the press.

The State Department said Friday that topics being discussed in Havana would include lifting caps on Cuban and U.S. diplomatic staff and limits on their movements outside Havana and Washington.

"They're down to sort of nuts and bolts," said John Caulfield, who was U.S. Interests Section chief from 2011 until last summer. He said other topics likely included housing for diplomats and U.S. shipments to the new embassy.

Mark Erwin, a former U.S. ambassador to Mauritius who met with Jacobson and Vidal earlier this month, said "both sides felt strongly that it would happen before April 10, prior to the April 10 meeting in Panama City, actual embassies."

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