ARRESTS in the London subway bombings — which appear to have been suicide bombings:

LEEDS, England — Four bombers, each believed to have been armed with a separate bomb, died in last week’s terror attacks on London, Sky News reported Tuesday, quoting police sources.

The latest development gives weight to the theory that the blasts were carried out by homicide bombers. There had been earlier speculation that the explosives were detonated remotely, with timing devices.

Earlier Tuesday, authorities detonated explosives while raiding one of several residences in northern England as sources said police in London identified the body of the bomber of a bus destroyed in multiple blasts last week.

Sky News also said a number of arrests had been made in Yorkshire.

Scotland Yard planned to hold a press conference at noon EDT.

Stay tuned.

UPDATE: Lots more news at the Counterterrorism Blog.