The Venezuelan ambassador to Colombia suffered what government sources believed was a heart attack today in the Embassy of the Dominican Republic, where he and 10 other ambassadors are being held hostage.

Later reports disputed the earlier information, however, and a Venezuelan Embassy spokesman said Ambassador Virgilio Lovera, 63, suffers from a malfunction of the inner ear, which causes dizziness and loss of balance.

Reporters outside the embassy said they heard other hostages call to Army officers for medical aid for Lovera, and a heart specialist reportedly went into the building to treat Lovera. The diplomat had been checked twice in the last week for high blood pressure, the government sources said.

Earlier today, the Uruguayan ambassador escaped from the embassy by knotting blankets together and lowering himself to the ground from the second floor.

Authorities said the leftist guerrillas fired three times as Fernando Gomez, 43, jumped into a garden in front of the embassy at 12:40 a.m. Reporters near the scene said however, that one of the shots might have been fired at the ambassador by a confused soldier.

Don't shoot, don't shoot! I'm the ambassador of Uruguay," Gomez shouted as he ran toward a car parked near the embassy.

Gomez was taken to a military hospital where he was pronounced in good health although he suffered bruises in the fall.

Gomez was seen at the hospital with one arm in a sling, apparently from an injury suffered in the original guerrilla attack.

Gomez is the first person to escape during the three-week-old standoff at the Dominican mission. At least 31 hostages remain in the embassy, including U.S. Ambassador Diego Asencio.

Members of a guerrilla group called M19 seized the embassy during a reception Feb. 27.

The guerrillas have demanded release of from Colombian jails of comrades who they say are political prisoners. They are also demanding a multimillion dollar ransom and safe conduct out of the country in exchange for the hostages' freedom.

In another development, Cuban President Fidel Castro has offered to allow the guerrillas to fly to Cuba with their hostages and the prisoners, the government announced tonight.

Cuban Ambassador Fernando Ravelo transmitted the offer last Friday to President Julio Cesar Turbay Ayala, who said he would bear it in mind for use if necessary, the government said.