Four Americans were injured in the bombings in London and two of them remained hospitalized Friday, State Department (search) spokesman Tom Casey said.

The other two also received hospital treatment and had been released, Casey said in a brief announcement that provided no details, except that all apparently were tourists.

Casey cited privacy regulations that limit what the U.S. government can say about American (search) casualties without permission from the injured or their families.

However, in Knoxville, Tenn., the family of two sisters said they had been injured in the bombings and were recovering at a hospital in London (search). One had surgery on her feet twice, the family said.

College students Kathleen "Katie" Benton, 21, and Emily Benton, 20, were on the London subway Thursday when a series of explosions targeted three subway stations and a double-decker bus.

"Both girls are alert and talkative. They will be moved to a semi-private room today so they can be together," according to information provided by the family on a Web site for Fellowship Church, where the Bentons worship.

At the State Department, Casey also said that the U.S. Embassy in London had resumed all its functions after limiting some services on Thursday.