By Euan Rocha and Alastair Sharp TORONTO (Reuters) - Canadian police have arrested two men and charged them with plotting to derail a Toronto-area passenger train in an operation that they say was backed by al Qaeda elements in Iran. "Had this plot been carried out, it would have resulted in innocent people being killed or seriously injured," Royal Canadian Mounted Police official James Malizia told reporters on Monday.

The surviving Boston bombing suspect has not yet been interrogated as he recovers in hospital from wounds sustained in a shootout, police said Sunday. Dzhokhar Tsarnaev, 19, is in "critical but stable condition," Boston Police Department Commissioner Ed Davis told reporters. He was taken into custody bloodied and seriously wounded Friday after an hours-long manhunt and an earlier shootout that killed his older brother Tamerlan, 26. "The suspect is not yet able to be interrogated by police," Davis said.

A suspected US drone strike in Yemen killed two Al-Qaeda militants and destroyed an arms cache on Sunday, a security official and witnesses said. The raid targeted a house in Wadi Abida, in the central province of Marib, where the two unnamed militants were killed, the official said, requesting anonymity. He said an arms cache in the house also exploded. Witnesses said an unmanned drone conducted the air raid, just like in most US air strikes that target Al-Qaeda suspects in the Arabian Peninsula nation, which is home to Al-Qaeda's most active branch.

By David Ingram and Deborah Charles (Reuters) - Federal prosecutors filed criminal charges on Thursday against a Mississippi man, who worked as an Elvis impersonator, for threatening to harm President Barack Obama by sending him a letter that initially tested positive for the deadly poison ricin.