Special to The New York Times

HAVANA, July 1-Four more Americans were kidnaped last night by the Cuban rebels, bring the total of abducted United States citizens to forty-five. Three Canadians also have been kidnaped.

Thirty or forty rebels entered the village of Guaro, fourteen miles from the Preston sugar mill, overpowered the company guards, and invaded the home of A. E. Smith, the mills agricultural superintendent. They told him he was being taken into the hills, but assured his wife, “We are not going to harm him and he will be released within a few days.”

In quick succession J. P. Stephens of Edmond, Okla., assistant agricultural superintendent, H. F. Sparks of Frankford Ind., and J. G. Ford, Both district superintendents, were seized be the rebels.

The wives of the last three are living in Santiago de Cuba, capital of Oriente Province.

In Havana, the United States Embassy said that no definite word had been received from Oriente Province concerning the release of twenty-eight United States sailors and marines of the United States Guantanamo naval base who were kidnaped earlier.

Nor has any word been received from the thirteen Americans and three Canadian kidnaped in the last week. They are employees of American Owned Moa Bay Mining company and Nicaro Nickel Company owned by the United States Government, both situated on the north coast of Oriente Province.

Regarding a report that the rebels had offered to release all of the Americans and Canadians if United States Ambassador Earl E. T. Smith would talk with Raul Castro, brother or Fidel Castro, leader of the revolt, an embassy spokesman here said this afternoon, “Ambassador Smith has no knowledge of such an ultimatum.”

A report from Las Villas Province said two freelance newspaper men from the United States were being held by military authorities in Santa Clara, capital of the province. According to the report, Richard Witzler of Toledo, Ohio, and Carlos Ferriero, a Venezuelan resident of the United States, came to Cuba early in June and visited the rebels in the Escambray Mountains of Las Villas Province. Several hundred youths, many from Havana University, had been fighting Government troops for months in the mountains.

It was said that the two were picked up at La Lima, Las Villas. Bot hare said to have passports. The United States Embassy in Havana declared it had no knowledge of these youths having been held by the military authorities.

Nicolas Rivero, brother of Dr. Andres [Rivero] Aguero, Presidential candidate for the four-party Government coalition in the elections next Nov. 3, was shot dead this afternoon in his home in Santiago de Cuba. Santiago de Cuba is the center of revolutionary activities. The two assassins were killed by policemen, the report said. The wife of Nicolas Rivero Aguero was wounded.