In the wake of the Pulwama terror attack, US national security adviser John Bolton told his Indian counterpart Ajit Doval on Friday that America supports India's right to self-defence as both sides vowed to work together to ensure that Pakistan ceases to be a safe haven for Jaish-e-Mohammad and other terror groups.

Doval and Bolton held a telephonic conversation on Friday evening during which they resolved to hold Pakistan to account for its obligations under the UN resolutions, and remove all obstacles to designate Jaish leader Masood Azhar as a global terrorist, the external affairs ministry said in New Delhi.

It said that Bolton supported India's right to self-defence against cross-border terrorism and offered all assistance to India to bring the perpetrators and backers of the attack promptly to justice.

The call was initiated by the US to express condolence and outrage over the Pulwama attack by Pakistan-based terrorist group Jaish-e-Mohammad.

At least 40 CRPF personnel were killed and many injured on Thursday in one of the deadliest terror attacks in Jammu and Kashmir when a Jaish suicide bomber rammed a vehicle carrying over 100 kg of explosives into their bus in Pulwama district.

'I told Ajit Doval today that we support India's right to self-defence. I have spoken to him twice, including this morning... and expressed the US's condolences over the terrorist attack,' Bolton told PTI.

He said the US has been very clear to Pakistan on ending support to terrorist safe havens.

'We have been very clear on that score... And, we are continuing to be in discussions we are going to have with the Pakistanis,' Bolton said.

Earlier, the White House and secretary of state Mike Pompeo asked Pakistan to end its support to terrorist safe havens inside the country.

'We stand with India as it confronts terrorism. Pakistan must not provide safe haven for terrorists to threaten international security,' Pompeo said on Twitter.

In a stern message to Pakistan, the White House asked Islamabad to 'immediately end' its 'support' to all terror groups and not to provide 'safe haven' to them, as the US condemned the brutal Pulwama terror attack.