The US embassy in Pakistan issued a warning on Friday about the catering company. 

"The US Embassy is aware of threat information suggesting that terrorist groups may have established links to the Hanif Rajput Catering Service," the embassy said.

The Times Square bomb plot has revived fears about Pakistan, a US ally, being a breeding ground for violence against US targets.

US prosecutors said Shahzad had admitted to being involved in the failed Times Square bomb attack and has been cooperating with investigators since his arrest on May 3.

Prosecutors said Shahzad, who has a wife and two children in Pakistan, had travelled to a Taliban and al-Qaeda stronghold in Pakistan to receive bomb-making training.