Pakistani authorities detained more than 5,000 suspected militants in two days since a suicide bomber attacked crowds in a busy park in the eastern city of Lahore on Easter Day, killing at least 70 people, a provincial minister said on Tuesday.

Investigators later released all but 216 suspects, who had been referred for further investigation, said Rana Sanaullah, a state minister for Punjab province from Prime Minister Nawaz Sharif's ruling party.

He said the raids were carried out by a mixture of police, counter-terrorism and intelligence agents and confirmed that army and paramilitary forces would be used in future operations.

"This operation will include all law enforcement agencies," Sanaullah said.