As the investigation continues into last week’s deadly London bombings, Capitol Police Chief Terrance Gainer said Monday that the department plans to keep tighter security measures in and around the Congressional campus in place for the foreseeable future.

Gainer said that while the department has modified some of its tactics, it plans to “still work very hot and heavy” and direct its attention to inspecting tour buses and other vehicles, as well as pedestrians with carry-on baggage such as backpacks and fanny packs.

The chief also said the force is adding manpower to the Capitol area, extending law enforcement shifts from eight to 12 hours and adding a constant presence along the perimeter of the complex. The force already has and will continue to aid Amtrak and D.C. Metropolitan Police with its policing of area transit.

The measures come on the heels of four bombings in London that left more than 50 dead and hundreds injured on July 7. The Homeland Security Department has increased the national terror alert level for mass transit services to orange, the second highest; at the Capitol, however, police officials did not raise the alert level.

“The good news for America continues to be that there doesn’t appear to be any direct credible threat against Washington or the Capitol,” Gainer said. “The bad news is the suspects are still at large and the forensic work is not completed as to what caused it all.”

Gainer met Monday morning with representatives of key local and federal law enforcement agencies to discuss the security situation. He said officials are concentrating most heavily on area transit — trains and Metro — and discussed sharing resources to ensure area safety.

The chief said he doesn’t foresee a time when the Capitol Police can ease its oversight of the campus. “Absent someone saying they promise never to blow up a train or a bus, I don’t know how we can not keep this up,” he said.

The move to keep tougher Capitol security measures in place follows similar decisions by Washington-area Metro and transit authorities, which also plan to stick with a tougher set of procedures indefinitely.

“We are still operating on an elevated threat level, which means more police officers and canine teams in stations, on trains and at railroads,” said Amtrak Police spokeswoman Tracy Connell. “We will continue at the level.”

Sgt. Joe Gentile, spokesman for the Metropolitan Police Department, echoed those sentiments. “Everything is the same. We will remain at a heightened state of alert until otherwise notified by the chief.”

The Capitol Police implemented a series of additional security measures, among them providing extra attention to anyone carrying a large item, such as a backpack or suitcase, anywhere on the Capitol grounds, and conducting “visual” inspections as well physical inspections if there is reasonable cause to do so.

Existing regulations already prohibit visitors from bringing large bags, as well as a variety of other items, into the Capitol, although Members and staff are not subject to the same restrictions.

Officers also are inspecting all large vehicles, including tour buses and limousines, entering the Congressional campus during morning and afternoon rush-hour periods.

In addition, officers have been reissued documents instructing them on how to identify and respond to potential suicide bombers.