Special to The New York Times
HAVANA, April 7 - Fighting between Government troops and rebels under the command of Fidel Castro has intensified in Oriente Province in the last forty-eight hours, official sources say toady.

[In Santiago, Cuban soldiers arrested six United States newsman. They were taken to Moncado Army Barracks where three of the Americans were held overnight. The other three, including Homer Bigart, of The New York Times, were released after a half-hour.]

A Cuban Army communique said seven rebels under the command of Raul Castro, a younger brother of the rebel chief, were killed in a clash in northern Oriente Province. The communique said thirty of the insurgent band were captured and the others were scattered and cut off from the main body of rebels on the Sierra Maestra.

First News of Capture

This was the first announcement by the army of the capture of the rebels. It is believed here that the army has been following a policy of taking no prisoners.

Army headquarters also reported that troops had shot down a C-46 plane carrying arms and ammunition to the rebels. The announcement said the plane crashed and burned, killing the pilot and crewmen. Some weapons were found in the wreckage, the army said.

Reports from Manzanillo said the rebels had burned a plane near there after it had brought arms and reinforcements for Señor Castro?s forces. These reports said the plane was destroyed because it could not take off in the field in which it had landed. There was no indication where the plane had come from.

Another clash between Government troops and rebels occurred Sunday at Dos Palmas near Santiago de Cuba. The army asserted that a number of rebels had been killed or wounded and that seven rifles and some ammunition had been seized.

Reports from Manzanillo, in the center if the guerilla war area, said it had been estimated there that Señor Castro had about 5,000 armed men.

Señor Castro declared “total war” in the Government if President Fulgencio Batista starting April 1. The rebel chief has said he would call a general revolutionary strike at the “opportune” moment. So far no strike has occurred.

President Batista told news men yesterday he was confident that his forces would defeat the rebels, but he conceded that it could be a long struggle.

Meanwhile, rebel sources in Havana declared an announcement by army headquarters Saturday that a rebel band led by Señor Castro had been cut off from the Sierra Maestra was without foundation.

An official of the consolidated Railway Company of Camaguey, which serves the eastern half of the island, also denied reports that the railroad’s employees had gone out on strike. The official said the rebels had burned so many railway bridges in the eastern part of Camaguey Province that it was impossible to maintain train service.