RAF MILDENHALL, England — Security levels remained unchanged at U.S. military facilities north of London, after the second incident in as many days heightened terror concerns in the capital.

London police shot a man dead on the city’s subway, one day after four men tried to explode bombs on the mass transit system.

“We’re still in Bravo,” said Capt. Jason McCree of the 48th Fighter Wing public affairs office at RAF Lakenheath, about 70 miles north of London.

Tech. Sgt. Cindy Dorfner of the nearby 100th Air Refueling Wing at RAF Mildenhall echoed that.

Bravo is a level of security when there is “an increased and more predictable threat of terrorist activity even though no particular target has been identified,” according to Defense Department guidelines.

The next level, Charlie, would be put in place if “an incident has occurred or intelligence has been received indicating that some form of terrorist action is imminent.”

A spokeswoman for the U.S. European Command in Stuttgart, Germany, said Friday afternoon that she has heard of no new advisory or change in security because of the recent incidents in London.

“There has been no change in our force-protection posture,” said Army Maj. Holly Silkman. Nor, she added, has the British government asked EUCOM for any help.

“If assistance is requested, of course we are going to help,” Silkman said.

Bruce Anderson, a spokesman for U.S. Army Europe, said Friday that it has been “business as usual” for the command. USAREUR, however, “continues to evaluate its mission and the threats” every day, especially when there is a possible terrorism incident.