New Delhi, May 2 -- The US has called on India and Pakistan to work together to de-escalate tensions against the backdrop of New Delhi's anticipated response to the terrorist strike in Pahalgam, with secretary of state Marco Rubio urging Pakistani officials to cooperate in investigating he "unconscionable attack". Rubio spoke to external affairs minister S Jaishankar and Pakistan Prime Minister Shehbaz Sharif late Wednesday night to discuss the fallout of the April 22 terror attack that killed 26 people in a scenic meadow in Jammu and Kashmir. Jaishankar told Rubio that the perpetrators, backers and planners of the terror attack "must be brought to justice", according to a social media post by the minister on Thursday. Rubio expressed sorrow at the loss of lives in the "horrific terrorist attack in Pahalgam" and reaffirmed the US's "commitment to cooperation with India against terrorism", US state department spokesperson Tammy Bruce said in a readout. Rubio also "encouraged India to work with Pakistan to de-escalate tensions and maintain peace and security in South Asia", she said. During his phone call with Sharif, Rubio spoke of the "need to condemn the terror attack" in Pahalgam and "urged Pakistani officials' cooperation in investigating this unconscionable attack", Bruce said in a separate readout. Rubio also "encouraged Pakistan to work with India to de-escalate tensions, re-establish direct communications, and maintain peace and security in South Asia", Bruce said. "Both leaders reaffirmed their continued commitment to holding terrorists accountable for their heinous acts of violence," she added. The phone calls by Rubio marked the first time that the US administration has reached out to the leadership of India and Pakistan since tensions between the two sides following the Pahalgam terror attack, which New Delhi said had "cross-border linkages". The calls followed Prime Minister Narendra Modi's decision on Tuesday to give the armed forces "complete operational freedom" to decide on the "mode, targets and timing" of India's response to the terror attack. Pakistan's deputy prime minister Ishaq Dar told a media briefing on Wednesday night that his country wouldn't resort to any escalatory action but will respond "very strongly" to any escalatory move by India, and reiterated Islamabad's call for an "independent" investigation into the Pahalgam terror attack. Sharif raised Pakistan's call for a "transparent, credible and neutral" investigation into the incident with Rubio during their phone conversation and rejected "Indian attempts to link Pakistan to the incident". A statement from the Pakistan government said: "He [Sharif] urged the US to impress upon India to dial down the rhetoric and act responsibly." The statement said Sharif shared Pakistan's perspective on developments since the Pahalgam attack with Rubio and condemned terrorism in all forms. Sharif claimed India's "provocations would only serve to distract Pakistan from its ongoing efforts to defeat terrorism", particularly from militant groups such as Islamic State-Khorasan Province, Tehrik-e-Taliban Pakistan and Balochistan Liberation Army "operating from Afghan soil". Sharif also raised with Rubio India's decision to suspend the Indus Waters Treaty, saying it was "regrettable that India had chosen to weaponise water" and that the treaty has no provision "for either side to unilaterally renege from its commitments". Sharif also contended the peaceful resolution of the Jammu issue is the only way to ensure lasting peace in South Asia. A day after the Pahalgam terror attack, India unveiled a raft of punitive measures, including suspension of the Indus Waters Treaty of 1960, closure of the only operational land border crossing at Attari, downgrading of diplomatic ties and revocation of visas for Pakistani nationals. Pakistan retaliated tit-for-tat counter-measures....