Conveying its grave concern, the US has asked Pakistan to follow through on its commitment to bring the attack perpetrators to justice.

"We are gravely concerned about the release on bail of alleged Mumbai attack mastermind Zakiur Rehman Lakhvi," State Department spokesperson Jeff Rathke told reporters on Friday in response to a question.

The US has "communicated that concern to senior Pakistani officials over the course of many months, and as recently as yesterday," he said, urging Islamabad to follow through on its commitment to bring the perpetrators of Mumbai attacks to justice.

"Terrorist attacks are an assault on the collective safety and security of all countries," Rathke said.

Lakhvi was released from Adiala Jail in Rawalpindi on Friday, a day after the Lahore High Court suspended his detention and ordered his immediate release.

Pakistan, the spokesman noted, "has pledged its cooperation in bringing the perpetrators, financiers, and sponsors of the Mumbai terrorist attacks to justice".

"We urge Pakistan to follow through on that commitment to ensure justice for the 166 innocent people, including six Americans, who lost their lives," he said.

Asked if the release would have any repercussions for Pakistan, Rathke said the US had conveyed its concern in Islamabad, but he would not "speculate about consequences or repercussions".

"But I think I've made clear that we're, again, as I said, gravely concerned about this development."