State Department (search) officials said Tuesday 14 Cuban diplomats have been declared "persona non grata" and have been given 10 days to leave the United States.

Seven diplomats at the Cuban Interests Section (search) in Washington, D.C. — there's no Cuban embassy because the U.S. has no diplomatic relations with Cuba — are being expelled for "inappropriate and unacceptable Cuban activities," a euphemism for espionage activities.

That's about one-third of the approximately 21 Cuban employees who work at the Interests Section.

Seven diplomats from the Cuban mission at the United Nations are also being kicked out for "activities deemed to be harmful to the U.S. outside their official capacity," once again, a euphemism for spying.

The move is the latest row in increasingly poor relations between Cuba and the United States. While diplomatic ties had been severed since Fidel Castro (search) took over the island nation in 1959, communications have been particularly strained since the war in Iraq. At that time, Castro began detaining dissidents, jailing 75 of them for up to 28 years and executing without a trial three hijackers who seized a ferry and tried to make a break for Miami.

Last week, the two nations exchanged tit-for-tats when the State Department required Cuban diplomats to go through the department to contract services like repairmen and housekeepers. The move echoed a similar imposition on U.S. diplomats in Cuba.

An official at the Cuban mission in New York told Fox News there is "no comment at this time" about the State Department decision.

Fox News' Teri Schultz contributed to this report.