President Reagan, frustrated by the hijacking of Trans World Flight 847 and recent terrorist attacks in El Salvador and West Germany, declared yesterday that "our limits have been reached" and warned that the United States would consider responses -- "military and otherwise" -- to end the violence.

White House spokesman Larry Speakes read a statement in which Reagan announced that he was rushing intelligence, law enforcement and military assistance to El Salvador in the wake of a shooting attack that killed 13 people, including six Americans.

But Reagan took a more restrained approach to the crisis in Beirut where 40 Americans are being held hostage. He announced that Vice President Bush would form a new task force to deal with international terrorism and that Bush would make the issue a key item of discussion during his trip to Europe next week.

Later yesterday, Alexandre Hay, president of the International Committee of the Red Cross, told Reagan in an Oval Office meeting that the organization is "standing ready" to help in the Beirut hostage crisis if "all sides ask us to do something." But he said that had not happened.

A White House official said Reagan did ask Hay if his organization would attempt to check on the "treatment, status and health" of the Americans held captive, and the president described the broadcast he had seen of the Beirut news conference involving some of the hostages.

The official said Hay responded that he was "happy to do that," that some effort had already been made to get permission from Nabih Berri, leader of the Shiite Amal movement, but that Berri had not provided "a final answer."

Meanwhile, the administration criticized a tumultuous news conference in Beirut involving five hostages from TWA Flight 847. Speakes denounced it as a "cynical exploitation of the hostages" by their captors. A State Department spokesman, Pete Martinez, said, "The hostages clearly were speaking under duress."

Reagan reiterated yesterday that the United States would not capitulate to terrorist demands.

The president's strongly worded statement came after a high-level meeting of his defense and foreign-policy advisers in the White House Situation Room.

"By our very nature, we are slow to anger and magnanimous in helping those in less fortunate circumstances," Reagan's statement said. "No nation on earth has been more generous to others in need. But we also have our limits -- and our limits have been reached. We cannot allow our people to be placed at risk simply because they are blessed with being citizens of this great Republic."

Reagan said terrorists are waging a war "against all of civilized society" in which "innocent civilians are intentional victims and our servicemen have become specific targets."

"This cannot continue," he said. "We must act against those who have so little regard for human life and the values we cherish." But Reagan said Americans should not respond "in pointless anger" and called for "reasoned responses to lawless actions by those who do not abide by the norms of civilized society."

He did not specify what those responses should be, but said they should be "appropriate and proportionate to the criminal acts which have been taken against our citizens." Asked whether Reagan was suggesting a response in-kind to terrorist acts, Speakes said, "Let those who are responsible for it wonder."

Speakes said Reagan was "drawing the line, laying out a specific plan of action."

In El Salvador, Speakes said, the administration is looking to the government of President Jose Napoleon Duarte to "find and punish the terrorists" with U.S. military, law enforcement and intelligence assistance. He ruled out any direct U.S. military actions, however.

In Lebanon, the White House continued to follow its approach of the past several days of taking a firm line against the hijackers in public comments while seeking a diplomatic solution to the impasse. Speakes said the administration is "redoubling our diplomatic efforts there, in order to bring pressure to bear on those who might have influence . . . . "

The president has all but ruled out military action to free the hostages, but Speakes yesterday seemed to suggest that did not preclude possible retaliatory strikes after they are released.

"We certainly have always maintained our military options as far as going to the heart of terrorism," and possibly striking "in a preventive fashion, if we feel that's necessary -- and there is always the option of preventing further incidents of this type, if we know where we're going."

Speakes said the administration's "first priority" was securing the safe and swift return of the hostages, adding, "What happens after that remains to be seen."

The spokesman said "we cannot draw the conclusion yet" of any connection between the Beirut and El Salvador terrorist acts. National security affairs adviser Robert C. McFarlane said the incidents indicated that "it's a time for testing. This kind of thing is not unprecedented in El Salvador, but it's the kind of thing that may be seen in the current climate as a time to test the United States . . . . "

Reagan continued to carry on a full regular schedule, including a series of honors presentations yesterday, and he plans to travel to Dallas today to push his tax revision plan. He refrained from mentioning the Lebanon and El Salvador crises in his public appearances yesterday.

The written statement read by Speakes was prepared before the Situation Room meeting and approved by the participants, including Secretary of State George P. Shultz, Defense Secretary Caspar W. Weinberger and McFarlane, among others, officials said.

The statement said Bush was being asked to convene the task force when he returns from Europe to "develop recommendations for my decision on how all available resources can best be brought to bear in dealing with this problem."