WASHINGTON: India protested Friday against the blocking of its latest bid to have Jaish-i-Muhammad chief Masood Azhar put on a United Nations terror blacklist following a deadly attack on an Indian air force base.

New Delhi wants the UN Security Council committee monitoring sanctions against Al Qaeda, the militant Islamic State (IS) and other extremist groups to designate Azhar as a terrorist. Jaish-i-Muhammad or Mohammad's Army, is already blacklisted.

Indian Foreign Ministry spokesman Vikas Swarup said the failure to designate Azhar is "incomprehensible" and demonstrates "a selective approach to combating terrorism". He was speaking on the sidelines of a nuclear security summit in Washington.

India most recently requested the designation of Azhar after the Jan 2 attack on the base in the northern town of Pathankot, near the Pakistan border, in which seven Indian soldiers died.

Swarup told reporters the attack "has shown that India continues to bear the dangerous consequences of not listing Masood Azhar. Given the proven networking of terrorist groups, this has implications for the entire international community."

Examine: Will Jaish crackdown salvage Pakistan, India talks?

An Indian diplomat said China put a "technical hold" on the designation. The diplomat was not authorised to comment on the issue and requested anonymity.

The sanctions committee, which includes all 15 Security Council members, decides on additions to the blacklist by consensus.

China is a permanent member of the council, with veto powers, and has longstanding ties to Pakistan.

Chinese Ambassador Liu Jieyi said that the request to add the militant leader to the UN Al-Qaeda/IS sanctions list did not meet certain requirements, but did not elaborate.

“Any listing would have to meet the necessary requirements,” said Liu. “It is the responsibility of all members of the council to make sure that these requirements are followed."

The UN banned Jaish in 2001 but India’s efforts to get restrictions imposed on Azhar after the Mumbai attacks did not bear fruit because China did not allow them to be imposed.

Pakistan’s Joint Investigating Team (JIT) investigating the Pathankot airbase attack in India told Indian interlocutors that it is yet to find evidence linking Masood Azhar to the terror attack, The Hindu reported on Wednesday.

According to The Hindu, the JIT was still verifying whether the Jaish founder had any role in the storming of the base.

Following Indian accusations earlier this year that militant group Jaish-i-Mohammad was responsible for the attacks, Pakistani authorities cracked down on the group, sealing a Jaish-run seminary in Sialkot and taking group leader Masood Azhar into protective custody.

The Indian Express said that Indian investigators had asked the JIT for the Jaish chief’s voice samples, indicating he was the prime suspect in the January 2 armed attack at the Indian Air Force base.

While the JIT probes the attack, reciprocity is being discussed by India. "We will ask for access to Masood Azhar," Sharad Kumar, the chief of India’s National Investigation Agency (NIA), told NDTV.

A formal request would be sent after the five-member Pakistani team returned home, he said at the time.

Also read: Lakhvi release: China defends decision to block India request at UN