Media playback is unsupported on your device Media caption Shaimaa Khalil in Islamabad and Sanjoy Majumder in Delhi report on the reaction

The suspected mastermind of the 2008 Mumbai terror attacks, Zakiur Rehman Lakhvi, has been released on bail from a Pakistani jail, officials say.

Jail officials in Rawalpindi said Mr Lakhvi was released on Friday morning.

India's Home Minister Rajnath Singh has called the release "unfortunate and disappointing", Indian media reports say.

Mr Lakhvi had been granted bail in December, but was kept in detention under public order legislation.

That detention was declared void by the High Court, which ordered his release.

Mr Lakhvi still faces trial - along with six other suspects - over the attacks, which left 166 people dead and damaged peace efforts between the two countries.

Image copyright AFP Image caption Mr Lakhvi's case has become a major issue in Indo-Pakistani relations

Analysis: M Ilyas Khan, BBC News, Islamabad

Zakiur Rahman Lakhvi's trial in the Mumbai attacks case still continues, but his release on bail suggests the legal evidence presented in court by prosecutors may not be enough for a conviction.

This contrasts with six years ago, when the interior minister at the time, Rehman Malik, provided graphic details of how a part of the Mumbai attacks conspiracy was hatched in Pakistan. Indian officials have since said that they also handed evidence against Mr Lakhvi and his comrades to Pakistani prosecutors.

Apparently, most of this evidence has not been made part of the case record, indicating legal complications and also perhaps a lack of interest on the part of Pakistani authorities.

Analysts say legal technicalities may be one factor behind his release. Another factor, according to some in the intelligence community, may be the fear in security circles that his "demobilisation" may hurt the morale of Kashmir-focused insurgents, something they say the government does not wish to see.

Profile: Lashkar-e-Taiba

The Mumbai attacks were blamed on militants of the Lashkar-e-Taiba group (LeT) which Mr Lakhvi was accused of heading.

He was arrested by Pakistan on 7 December 2008, four days after he was named by Indian officials as one of the major suspects.

A spokesman for Jamaat-ud-Dawa, a charity accused of links to LeT, said Mr Lakhvi was "free now and in a secure place".

"We can't say exactly where is he at the moment for security reasons," the official told AFP.

Image copyright AFP Image caption The prospect of Mr Lakhvi's release sparked some angry protests in India

Mr Lakhvi had been receiving special treatment during his time in prison.

Jail officers said he, along with six of his comrades, had several rooms at their disposal. They had access to a television, mobile phones and the internet, as well as dozens of visitors a day.

These privileges had allowed him to remain in effective contact with the LeT rank and file, the officials said.

Elements in the Pakistani establishment are known to have provided such facilities to jailed militant commanders whom they believe they may need in future.

The court order to free Mr Lakhvi on bail caused controversy as it came just after militants carried out a massacre at a school in Peshawar last December.

The attack prompted the civilian and military leadership to come together to make a rare call for action against "all shades of terrorism".