Pakistani prosecutors have approached a court seeking voice samples of seven men, including LeT commander Zakiur Rehman Lakhvi, charged with involvement in the 2008 Mumbai attacks, saying the measure will speed up their prosecution.

Special prosecutor Chaudhry Zulfiqar Ali of the Federal Investigation Agency filed an application that was admitted for regular hearing by the Islamabad High Court yesterday.

Prosecutors also filed a separate application that asked the court to declare Indian terror suspect Fahim Ansari a "proclaimed offender" or fugitive.

A two-judge bench issued notices to the seven suspects, asking them to respond to the FIA's application seeking their voice samples.

Ali contended that the voice samples would help prosecute the seven suspects, who have been on trial since 2009.

"The Indian government had sent the alleged voice samples of the seven accused facing trial here. If the court allows us to obtain their voice samples, the truth will be before everyone," he told PTI.

The FIA has for long been seeking voice samples of the seven accused so that they can be compared with recordings provided by Indian authorities.

The recordings include intercepts of communications between the attackers in Mumbai and their handlers in a control room in Karachi.

Lawyers defending the seven suspects have blocked earlier attempts to obtain voice samples by using loopholes in Pakistan's existing anti-terrorism laws.

"If the voice samples are ignored, the prosecution cannot establish the guilt of the accused," Ali said.

In the second application, FIA prosecutor Chaudhry Azhar asked the High Court to declare Fahim Ansari, an Indian accused in the Mumbai attacks, a fugitive.

Earlier, an anti-terrorism court of Rawalpindi that is conducting the trial of the seven Pakistani suspects had issued a non-bailable warrant for Ansari.

A court in Mumbai has acquitted Ansari in the Mumbai attacks case but he continues to be in custody for other offences.

Azhar contended that Ansari was trained by the Pakistani suspects and sent to India to facilitate the Mumbai attacks.

Special prosecutor Ali said declaring Ansari a fugitive will help strengthen the case against the seven accused in Pakistan.

"As Ajmal Kasab is no more, declaring Fahim Ansari a proclaimed offender will help strengthen our case against the accused," he said.

Ali was referring to Kasab, the lone surviving terrorist involved in the attacks who was hanged in a jail in Pune last year.

He said the FIA had earlier named Kasab in an FIR registered in 2009.

"In his confessional statement, Kasab had implicated the accused in Pakistan," he said.

The date for the hearing of the FIA's applications will be fixed by the Islamabad High Court in April.