Congress president Sonia Gandhi and former prime minister Manmohan Singh on Monday met former finance minister P. Chidambaram in Tihar Jail, where he is currently lodged in connection with the INX media case.

The move is politically significant because the Congress is of the view that its senior leaders need to speak out in Chidambaram’s support. The party alleges political vendetta by the ruling Bharatiya Janata Party (BJP).

“I am honoured that Smt. Sonia Gandhi and Dr. Manmohan Singh called on me today (Monday). As long as the @INCIndia party is strong and brave, I will also be strong and brave," read a Twitter post by Chidambaram, who asked his family to post on his behalf.

The meeting lasted nearly half-an-hour.

Singh later issued a statement saying he was “concerned with continued detention in custody" of Chidambaram.

Watch video: Sonia Gandhi & Manmohan Singh meet P Chidambaram in Tihar jail

“If the officers are not at fault, it is beyond our comprehension how the (former) minister who simply approved the recommendation can be accused of committing an offence. If the minister is liable for approving a recommendation, whole system of government will collapse," Singh said.

Over the past few weeks, top Congress leaders and alliance partners, including Dravida Munnetra Kazhagam (DMK), have issued statements supporting Chidambaram.

On Monday, Gandhi and Singh were accompanied by Chidambaram’s son Karti Chidambaram.

The former finance minister on Monday filed a rejoinder to the counter-affidavit of the Central Bureau of Investigation (CBI) in relation to the proceedings of the bail application moved by him. The arguments on his bail plea were part heard on Monday and will be continued on Tuesday. Chidambaram in his rejoinder denied that cogent evidence incriminating him is already on record.

Chidambaram was sent to judicial custody on 5 September, after the CBI custody in the INX Media case ended.