The New York Police Department has stepped up security outside major television news outlets in Manhattan to prevent possible takeovers by terrorists who may want to broadcast anti-American messages.

"It's a concern, especially with international television companies," police Commissioner Raymond Kelly said Tuesday as he announced a security plan for the city in the event of a war overseas.

New York's 36,500-officer police department, the nation's largest, began formulating the sweeping Operation Atlas security plan as war with Iraq grew more certain in recent weeks. The plan arose from fears that the city could become a target for retaliation by terrorists.

The operation, which could cost more than $5 million a week, is "the most comprehensive terror prevention program our city has implemented," Mayor Michael Bloomberg said.

On Wednesday, Bloomberg went to Washington to ask President Bush and Homeland Defense Secretary Tom Ridge for more federal dollars to meet the city's anti-terror "special needs."

The mayor emerged from the Oval Office with Ridge and described their meeting as "very productive," though "no figures, no final determinations have been made."

The city would like current homeland defense spending formulas, which dole out money based on population, changed to reflect the higher level of threat that New York faces.

Ridge praised the city's security plan, calling it "a model for other communities to follow."

As part of Operation Atlas, police officials are deploying special patrols to guard television stations clustered in midtown Manhattan and elsewhere.

The step was not prompted by a specific threat or intelligence, police said. But counterterrorism experts and broadcast executives have viewed television news studios as potential targets since the Sept. 11 attack.

Once the war begins, police plan to mobilize hundreds of extra officers to patrol in and around locations considered susceptible to suicide bombings or other attacks -- including places of worship, landmarks, tourist attractions, Wall Street and train stations. Other officers will staff checkpoints at bridges and tunnels in Manhattan and elsewhere.

The NYPD will pay special attention to ferry boats and subways, where officers have been running drills to converge on train cars and platforms at the first sign of trouble. Officers plan to use dogs trained to sniff for explosives.

Kelly stressed that tourist sites were open.

"We're doing everything we can to keep them open," the commissioner said in an interview Wednesday on NBC's Today show.

"The city is the safest big city in America. We encourage people to come to the city's tourist sites," he added.

The department has already deployed heavily armed units known as Hercules teams to visit potential targets such as Times Square. Separate units have been trained to detect and contain biological and chemical hazards.

Bloomberg said the plan would include the resumption of military flight patrols above the city. In a related move Tuesday, the Federal Aviation Administration put tighter restrictions on airspace in a 30-mile radius around John F. Kennedy International Airport.

Operation Atlas calls for police commanders in each of the five boroughs to develop plans to operate as independent departments if police headquarters in Manhattan is disabled.

Much of the operation's cost involves officer overtime. Democratic Sen. Charles Schumer has asked the White House to reimburse the city for the expense.

"I understand that these patrols are expensive, but the price we paid on Sept. 11 was high as well, and the price we could pay if round-the-clock patrols cease could be far greater," Schumer wrote in a letter to Bush.