The accident appeared to have been caused by a structural failure, officials said.

The explosion initially appeared to have been caused by a gas leak.

The police said the blasts appeared to have been caused by bombs made with dynamite.

He said the accident appeared to have been caused by excess speed.

No one was injured in the blast, which appeared to have been caused by a bomb.

Another official said the crash appeared not to have been caused by hostile fire.

The spokesman said the problem appeared to have been caused by a change in suppliers during production of the engines.

The fire appears to have been caused by a malfunctioning fan.

The police said her death appeared to have been caused by ingestion of water and hypothermia.

Initial problems with the ceiling appear to have been caused by water penetrating through the floor above.