Congressional leaders expressed bipartisan support last night for President Reagan's decision to order an air strike against Libyan targets but warned that Americans should be prepared for possible retaliation by Libyan leader Muammar Qaddafi.

Some lawmakers also questioned whether the air strike would lead to a spiral of violence between the United States and countries it holds responsible for terrorist actions against Americans.

The strongest support came from Senate Republicans, including Majority Leader Robert J. Dole (R-Kan.) and Foreign Relations Committee Chairman Richard G. Lugar (R-Ind.), who were among a bipartisan group of lawmakers briefed by Reagan and others at the White House about three hours before the attack.

"I think the president has taken the right action," Dole said last night, characterizing the air strike as "an act of self-defense." He added: "I believe the president did what people want him to do -- a proportionate response to an act of terrorism . . . . "

Lugar said, "It was the logical next step. The United States has responded in an appropriate and a proportional manner to the terrorist attack on our citizens and soldiers in Berlin.

"In previous situations, we tried diplomatic, political and economic sanctions to no avail. The air strike sends the strong message to Libya that the United States will not tolerate the indiscriminate violence of terrorism against us."

However, Senate Minority Leader Robert C. Byrd (D-W.Va.) questioned where last night's military action might lead.

"If this is the policy -- tit for tat, tit for tat -- where does this take us? What is next? Syria?" Byrd asked.

Byrd also complained that the White House meeting "was not consultation . . . We were called down to be notified."

He said he understood the need for secrecy but thought that some congressional leaders should have been informed of administration plans as they developed, as required by the War Powers Resolution.

A similar cautionary note about possible consequences of the antiterrorism policy voiced by Reagan last night was raised by House Minority Leader Robert H. Michel (R-Ill.). He said he supported the president's decision to attack Libya, but added:

"We are in a new kind of war here, breaking new ground. It will take time to shake all this out. I have to express some concern. What is the next step? What if it comes from another country? What is the retaliation?"

The White House response to these questions last night was that U.S. action will depend on circumstances at the time.

There were indications that congressional leaders summoned to the White House raised questions about the extent of consultations with Congress and the possible consequences of the military action.

One participant said that Michel played the role of "devil's advocate" and that questions were raised by others, including Byrd, ranking Senate Armed Services Committee Democrat Sam Nunn (Ga.) and ranking Senate Foreign Relations Committee Democrat Claiborne Pell (R.I.).

With only routine business pending here, House Democratic leaders were scattered nationwide yesterday and did not attend the White House meeting.

An aide to House Majority Leader James C. Wright Jr. (D-Tex.) said Wright, in Fort Worth, was briefed by a White House official by telephone at about 5 p.m. Neither Wright nor House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.), in Boston, issued statements.

Other Democrats quickly expressed support. "I think all Americans would stand with the commander-in-chief at this moment," Sen. Edward M. Kennedy (D-Mass.) said.

Nunn said he hopes that the air attack eventually "will deter what I call state-supported terrorism." Asked if the action would make travel abroad safer for Americans and reduce terrorism, Nunn said:

"Not in the short run. The best we can hope for is that we begin to deter state-supported terrorism. I think it is a mistake to view Qaddafi as the only source of terrorism. He's the loudest and most obnoxious, but he's not the only element in terrorism. So we may have some rough sailing in the short haul."

Robert G. Torricelli (D-N.J.), a liberal member of the House Foreign Affairs Committee, indicated the bipartisan nature of the congressional support for the air strike, saying:

"I don't think you're going to find any divisions in either house. We needed an appropriate response, and this is it."

In Detroit, Robin Beecham said, "I think we did the right thing." Beecham's brother, Army Sgt. Kenneth Ford, was killed April 5 in the West Berlin nightclub bombing attributed by the administration to Libyan-directed terrorists.