WASHINGTON — President Reagan, in a secret report to Congress outlining his plans for aid to the rebels fighting Nicaragua's leftist regime, says he wants to increase the guerrilla force from an estimated 16,000 troops to as many as 35,000 and escalate their war to force the Sandinista government to accede to U.S. demands.
The top-secret document, excerpts of which were made available Wednesday, also warns that "the direct application of U.S. military force" against Nicaragua is possible "if other policy alternatives fail."
The report, submitted to Congress two weeks ago as part of Reagan's formal request for $14 million in aid for the rebels, is the fullest official explanation so far of the Administration's plans in Nicaragua.
Early Accord Unlikely
It suggests that Reagan believes an early peace agreement between the rebels, known as contras , and the leftist Sandinista regime is unlikely. Reagan's request for the aid included a proposal to give the two sides 60 days to begin peace talks but some senior officials have acknowledged that they doubt that will happen.
It also implies that if the Administration wins the $14 million in Congress next week, it will soon ask for more money--a prospect that Robert C. McFarlane, Reagan's national security adviser, confirmed Wednesday.
"The sentiment in support of (the contras), once expressed, has to be sustained in this country in successive votes to come," McFarlane said. "What it will involve in terms of money can't be predicted right now."
'Create Real Pressure'
Reagan's report to Congress says the Administration wants to enlarge the rebel army to "levels sufficient to create real pressure on the government of Nicaragua." It added that a 20,000- to 25,000-man force in northern Nicaragua and a 5,000- to 10,000-man force in southern Nicaragua could achieve that objective.
One key congressman estimated that an army of 35,000 could need as much as $100 million a year to sustain operations--"which they clearly aren't going to get," he added. But Administration officials said their estimates are considerably lower and predicted that, if Congress approves the current request, the rebels could win substantial amounts of private and foreign aid.
The Administration already has requested $28 million in additional CIA funding for the rebels in its budget for fiscal 1986, which begins Oct. 1.
'An Eventual Option'
The White House report warned: "The direct application of U.S. military force . . . must realistically be recognized as an eventual option, given our stakes in the region, if other policy alternatives fail."
Administration officials said Reagan has no intention of using U.S. force directly against Nicaragua, but said that sentence in the report was included to suggest to Congress that aid to the contras is one way of avoiding military involvement.
"The President has said it is not his policy to put troops in there," Assistant Secretary of State Langhorne A. Motley told a House subcommittee hearing. "The President has also said a President should never say never," Motley added.
One key Democratic congressman, who spoke on condition that he not be identified, called the warning "an extraordinary statement."
"It seems to me that the President is putting himself into a box," he said. "He's saying that if this policy doesn't work, our interests are so vital that we have to intervene. The effect of that is to build a kind of inexorable momentum toward military action."