Police in Bangladesh are questioning the wife of Akayed Ullah, a Bangladeshi man US authorities say set off a pipe bomb in a crowded New York City commuter hub, two senior police officials in Bangladesh said on Tuesday.

The two officials, who declined to be identified as they are not permitted to discuss the matter publicly, did not give details of the questioning but said the couple have a six-month old baby boy.

Ullah set off an explosion in an underground pedestrian corridor between New York's Times Square and the Port Authority Bus Terminal at rush hour on Monday, injuring himself and three others in what New York Mayor Bill de Blasio called an attempted terrorist attack.