WASHINGTON - Homeland Security Secretary Tom Ridge said today that new information on a terrorist threat against the United States "talks about an attack" but said there is no need to raise the national alert level.

"I can confirm that we have seen for the past several weeks a continuous stream of reporting that talks about the possibility of attacks on the United States," he said, "but not unlike what we've seen for the past several years."

Appearing on morning television news shows in advance of a news conference scheduled later today by Attorney General John Ashcroft and FBI Director Robert Mueller, Ridge said of potential terrorists on U.S. soil: "It's our job, obviously, to try to identify who they are and apprehend them."

U.S. counterterrorism and law enforcement officials had said Tuesday that new intelligence indicates that a group of terrorists already deployed inside the United States is preparing to launch a major attack this summer. This information was described by a senior counterterrorism official on condition of anonymity as extremely credible and backed by an unusually high level of corroboration.

But Ridge, interviewed on NBC's "Today" show, said there are no current plans to lift the national alert status from Code Yellow, where it currently stands. That's the midlevel alert level on a five-step warning program, higher than green and blue but lower than orange and red.

"First of all, every day we take a look at the overall threat reporting that we receive," Ridge said. "There's not a consensus within the administration that we need to raise the threat level. ... We do not need to raise the threat level to increase security. Right now, there's no need to put the entire country on a (elevated) national alert."

"At some of the higher-profile events, you had better believe there will be additional security," Ridge said on CBS's "The Early Show."

The intelligence does not include a time, place or method of attack but is among the most disturbing received by the government since the al-Qaida attacks of Sept. 11, 2001, the senior counterterrorism official said.

"There is clearly a steady drumbeat of information that they are going to attack and hit us hard," the official said.

Ashcroft and Mueller were to outline an intensive effort by law enforcement, intelligence and homeland security officials to detect and disrupt any potential plots. And the FBI was dispatching a bulletin to some 18,000 state and local law enforcement agencies warning of the threat.

Beginning with Saturday's dedication of the new World War II Memorial in Washington, the summer presents a number of high-profile targets in the United States. They include the G-8 summit in Georgia next month that will attract top officials from some of America's closest allies, plus the Democratic National Convention in Boston in July and the Republican National Convention in August in New York City.

The FBI and Homeland Security Department also are concerned about so-called soft targets such as shopping malls anywhere in the United States that offer a far less protected environment than a political convention hall.

Of special concern, the counterterrorism official said, is the possibility that terrorists may possess and use a chemical, biological or radiological weapon that could cause much more damage and casualties than a conventional bomb.

Los Angeles police held a news conference Tuesday to reassure the public.

"We would be foolhardy to ignore those statements, but I think it would be irresponsible to panic," said John Miller, head of the LAPD counterterrorism bureau.

New York Police Commissioner Raymond Kelly said city officials had not been advised that terrorists were plotting an attack there.

"We are receiving highly sensitive intelligence information on a regular basis, including today, and there is nothing in that reporting to indicate a specific threat or looming attack against New York City," Kelly said in a statement late Tuesday.

The FBI already has created a special task force that is focused solely on dealing with this summer's threat. The task force, whose existence until recently was classified, is intended to ensure that no valuable bits of information or intelligence fall through the cracks, as happened before the Sept. 11 attacks.

Other actions to be taken include new FBI interviews with people who may have provided valuable information in the past, distribution of photos of individuals sought for questioning and a fresh examination of older investigative leads to determine whether they might point to elements of the summer plot.

U.S. authorities have said repeatedly that al-Qaida is determined to mount an attack on U.S. soil, in part to announce to the world that it remains capable of doing so despite the money and effort that has gone into homeland security since the Sept. 11 attacks.

There also is concern terrorists might try to mount an attack to coincide with the November election. The political fallout from the March 11 train bombings in Spain taught al-Qaida that an attack timed to an election can have a major impact. Spain's former ruling party was ousted in the voting that followed the bombing, which killed 191 and injured more than 2,000.

The official did not say how many suspected al-Qaida or other terrorist operatives are believed in the country, whether they made their way into the United States recently or have been here for some time.

Special security attention already is being focused to the nation's rail, subway and bus lines.