Chief of Army Staff General (COAS) Qamar Javed Bajwa in a call with US Secretary of State Mike Pompeo on Friday emphasised "need for maximum restraint and constructive engagement" following the killing of top Iranian commander Qasem Soleimani.

Maj Gen Soleimani was killed on Friday morning in a US strike on Baghdad's international airport, in a dramatic escalation of tensions between the two countries.

The Pentagon said US President Donald Trump ordered Soleimani's "killing", after a pro-Iran mob this week laid siege to the US embassy in Baghdad. Meanwhile, Iranian Supreme Leader Ayatollah Ali Khamenei vowed to exact “severe revenge” for the general's death.

Read: Trump says Soleimani should have been killed 'many years ago'

Taking to Twitter, Pompeo shared that he had reached out to officials from multiple countries, including Bajwa, German Minister for Foreign Affairs Heiko Maas, French Foreign Minister Jean-Yves Le Drian, and Afghan President Ashraf Ghani.

"Pakistan's Chief of Staff General Bajwa and I spoke today about US defensive action to kill Qasem Soleimani," shared Pompeo on Twitter, adding the "Iran regime’s actions in the region are destabilising and our resolve in protecting American interests, personnel, facilities, and partners will not waver".

Shortly after, Inter-Services Public Relations (ISPR) via Twitter confirmed that the two had spoken. "COAS received telephone call from US Secretary of State Mike Pompeo. Regional situation including possible implications of recent escalation in Middle East was discussed."

"COAS emphasised need for maximum restraint and constructive engagement by all concerned to de-escalate the situation in broader interest of peace and stability," said the army's media wing in another tweet. "COAS also reiterated the need for maintaining focus on success of Afghan Peace Process."

Pakistan expresses 'deep concern'

Earlier, the Foreign Office via a statement expressed "deep concern" over the tensions, urging all sides to exercise restraint.

"Pakistan has viewed with deep concern the recent developments in the Middle East, which seriously threaten peace and stability in the region," said the statement.

"Respect for sovereignty and territorial integrity are the fundamental principles of the UN Charter, which should be adhered to," the statement said, adding that it is "important to avoid unilateral actions and use of force".

Also read: Qasem Soleimani — the general who became an Iran icon by targeting US

The statement urged all parties involved to "exercise maximum restraint, engage constructively to de-escalate the situation, and resolve issues through diplomatic means, in accordance with UN Charter and international law".

Supporters of Majlis-e-Wahdat-e-Muslimeen (MWM) chant slogans to mourn the death of Iranian Major-General Qassem Soleimani, in Karachi, on Friday. — Reuters

Senators demand foreign policy briefing

During a session of the Senate today, members of the opposition demanded that Foreign Minister Shah Mehmood Qureshi appear in the upper house and brief lawmakers on the country's stance on tensions developing in the Middle East.

While addressing the sitting, former Senate chairman Raza Rabbani said the US's killing of Soleimani has given rise to new tensions in the region.

He said the worsening US-Iran relationship could have implications for Pakistan's economy and national security. "The foreign minister should tell the house what is Pakistan's stance on this and where it stands," the PPP leader added.

A photo posted by Instagram (@instagram) on Mar 22, 2015 at 11:21am PDT

Leader of the Opposition in the Senate Raja Zafarul Haq said the developing situation in Pakistan's neighbourhood demanded that the foreign minister brief the parliament on the issue. He said the minister should hear the Senate's opinion on the regional tensions.

PPP Senator Sherry Rehman said the Iranian general's killing could trigger a "serious crisis-like situation" in the Middle East.

"We will also have to hold discussions on this and when the parliament takes decisions it is for the country's survival and to save governments," she added.

"You must recall that the parliament had decided on non-interference. The country earns respect this way and the government's dignity is also elevated."

She said every Pakistan had questions regarding the foreign policy and regretted the absence of ministers in the house. "This house has not been taken seriously," Rehman added.

Senate Chairman Sadiq Sanjrani directed Foreign Minister Qureshi to appear before the house on Monday and give a policy statement on the US-Iran tensions.

In Qureshi's absence, Leader of the House in the Senate Shibli Faraz read out the government's response to the regional situation. He said the government is "monitoring" the US-Iran tensions while also assessing the international reaction to the developments.

Faraz said a report will be presented in the upper house regarding the US-Iran rift.