"Our foreign secretary has written to India's foreign secretary to provide additional evidence so that Mumbai case trial is competed. The response from the Indian side is still awaited," Foreign Office Spokesman Nafees Zakaria said at a press briefing.
Zakaria, however, did not elaborate when exactly the letter was written.
Pakistan arrested seven LeT-linked militants, including Lakhvi, for their role in the 2008 Mumbai attack in which 166 people were killed.
Mumbai attack mastermind Lakhvi, Abdul Wajid, Mazhar Iqbal, Hamad Amin Sadiq, Shahid Jameel Riaz, Jamil Ahmed and Younis Anjum are accused of abetment to murder, attempted murder, planning and executing the Mumbai attack.
Lakhvi is living at an undisclosed location after he got released from jail on bail a year ago. The other six suspects are in Adiala Jail Rawalpindi.
The case has been going on in the country for more than six years.
India has been urging Pakistan to complete the trial at the earliest. It has said that enough evidence has been shared with Islamabad to prosecute the accused.
However, Pakistani officials say India has not provided enough evidence needed to successfully complete the trial.
Meanwhile, Zakaria also said that the dialogue was the only option to resolve all outstanding issues with India.
"It has been said many times earlier that peace talks is the only way forward for relations between Pakistan and India," he said.
Asked about threats against Pakistani artists in India by extremists, he said there are many other people in India who welcome and support artists and promote people-to-people exchanges between the two countries.
"Both India and Pakistan agree that atmospherics should be improved and people-to-people contacts always help," Zakaria said.
He said religious tourism is part of such efforts and Pakistan has been encouraging it.
Zakaria also said that influential United States Senator John McCain would shortly visit Pakistan and hold important talks on various issues.
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