Updated

House Speaker John Boehner on Monday ordered flags flying over the U.S. Capitol to be lowered to half staff, out of respect for the victims of the Boston Marathon tragedy.

“Words cannot begin to express our sorrow for the families who are grieving so suddenly right now,” said Boehner, R-Ohio.  “The House of Representatives offers its prayers to the victims and the city of Boston.

Two bombs exploded near the finish line of the marathon at about 3 p.m. ET, killing at least two people and injuring dozens of others, authorities say.

No suspects have been identified, but the incident is believed to be an act of terror.

“We also give thanks for the professionals and Good Samaritans who prevented further loss of life,” Boehner also said. “This is a terrible day for all Americans, but we will carry on in the American spirit, and come together with grace and strength.”