The family of a man accused of setting off a pipe bomb in a crowded New York City subway corridor have said they are heartbroken and deeply saddened by the suffering the attack has caused.

In a statement, Akayed Ullah’s family also said they were outraged by the way investigations into the incident had been handled by law enforcement, which included pulling a teenage relative from class and questioning him without a parent, guardian or attorney present.

The family said they expected more from the justice system, in the statement released by Albert Fox Cahn, legal director for the Council on American-Islamic Relations in New York.

Ullah, an immigrant from Bangladesh, was the only person seriously hurt in the blast during the Monday morning rush hour that sent commuters scurrying in panic.

In a statement, the government of Bangladesh condemned the attack, saying: “Bangladesh is committed to its declared policy of ‘zero tolerance’ against terrorism, and condemns terrorism and violent extremism in all forms or manifestations anywhere in the world”

Police in Bangladesh said yesterday that they were not in a position to comment on the suspect.

US law enforcement officials earlier said the pipe bomb had been ignited with a Christmas light, matches and a nine-volt battery.

The short pipe was packed with explosive powder, but did not work as intended and the blast was not powerful enough to turn the pipe into deadly shrapnel.

Law enforcement officials familiar with the investigation said Ullah had looked at Islamic State group propaganda online and told investigators he was retaliating against US military aggression.

The blast on Monday injured three people besides Ullah, who was being treated in hospital.

President Donald Trump said the blast in Manhattan highlighted the need for an immigration overhaul.

He said the US “must fix its lax immigration system, which allows far too many dangerous, inadequately vetted people” into the country.

He pointed to his controversial travel ban as an example of the kind of policy that needed to be put in place.

And he called on Congress to end “chain migration”, in which people are permitted to join members of their family who have already immigrated.

Mr Trump also said people convicted of terror acts “deserve the strongest penalty allowed by law, including the death penalty in appropriate cases”.