During the phone conversation between the two leaders, May welcomed Khan's commitment to reduce tensions following the return of captured Indian Air Force pilot Abhinandan Varthaman by the Pakistani authorities earlier this week.
"The Prime Minister spoke to Pakistan's Prime Minister Imran Khan today. She welcomed his commitment to reducing tensions with India, and the return of Wing Commander Abhinandan, a Downing Street spokesperson said.
"The leaders discussed the need to address the causes of this conflict. The Prime Minister emphasised the importance of Pakistan taking action against all terrorist groups, in support of global efforts to combat terrorism, the spokesperson said.
Both leaders also "reiterated their commitment" to the UK-Pakistan bilateral relationship during the interaction, which follows heightened tensions between India and Pakistan following a terrorist attack in Pulwama district of Jammu and Kashmir on February 14.
Pakistan-based Jaish-e-Mohammed terror group had claimed responsibility for the suicide attack in which 40 CRPF soldiers were killed.
After the Pulwama attack, the Indian Air Force carried out a counter-terror operation, hitting what it said was a JeM training camp in Balakot, deep inside Pakistan on February 26. The next day, Pakistan retaliated with a large air formation, comprising 24 fighter jets, including F-16s.
Varthaman, who was in one of the eight MiG-21s that took on the invading Pakistan Air Force jets and shot down an F-16, was released at the Wagah border on Friday.
The UK government has repeatedly called for a de-escalation of tensions between India and Pakistan since the Pulwama attack on February 14, with senior government ministers holding talks with their counterparts in India and Pakistan.
During an urgent question in the House of Commons on Wednesday, UK Foreign Office minister Mark Field had told MPs that the UK would continue to support a listing of Jaish-e-Mohammed and its leader, Masood Azhar, under a UN Security Council Resolution.