Pakistan in talks with Saudi Arabia to send combat troops to protect the kingdom
Plans are under way to dispatch a brigade-sized deployment following a request from Riyadh, which wants the troops as an emergency response force. A brigade is usually made up of between 1,500 and 3,500 troops.
Islamabad and Saudi Arabia have long had a close military and security relationship, with troops from Pakistan's large and combat-hardened army regularly deployed for training Saudi soldiers. Although the kingdom, like other Arab Gulf countries, does not make the numbers public, experts say there are as many as 70,000 Pakistanis serving across the Saudi military services at any one time.
But requests for Pakistani combat brigades have usually only been made during times of heightened tensions in the kingdom.
Pakistani combat troops were sent after the 1979 attack on the Grand Mosque complex in Mecca by a proto-Al Qaeda extremist group and the Iranian revolution of the same year.
Forces from Pakistan were based in Saudi Arabia during the first Gulf War when the kingdom feared attack by Saddam Hussein.
Again, a decade ago, they were deployed as the US military ramped up operations to crush Al Qaeda in Iraq, prompting fears that the extremists would flee across the Saudi border, and as the militant group carried out a violent terrorist campaign within the kingdom.
A senior Pakistani military source confirmed the Saudi request, but stressed troops would "not go across the border" with Yemen, where Saudi Arabia is leading an Arab military coalition, of which the UAE is part, against the Iran-backed Houthi rebel movement.
Instead, the source said troops would be kept on standby in case of any major internal security threat or terrorist incident.
The deployment - which another Pakistani source claimed was still at the planning stage - comes at a sensitive time in Saudi Arabia's relationship with Islamabad.
Analysis: How Pakistan's military offers the Gulf much more than boots on the ground
The deployment of Pakistani troops to Saudi Arabia would cap a diplomatic push by Islamabad's army chief and prime minister, who have visited the kingdom, Kuwait, Qatar and the UAE in recent weeks. A number of economic and security interests have aligned to underscore the strategic importance of the relationship for both sides.
In 2015, the Pakistani parliament voted to turn down a request by Saudi Arabia to join its coalition fighting the takeover of Yemen by the Houthis and their allies. Members of Pakistan's parliament opted instead for a neutral stance on the Yemen conflict, fearing it would jeopardise their efforts to balance relations with the kingdom and Iran.
At the time, the Pakistani military was also wary of any involvement in a foreign war because its forces were overstretched fighting Pakistani Taliban and other extremist groups in the north-western tribal areas and elsewhere within the country's borders. That offensive has ended and an intelligence-led operation requiring less manpower has taken its place.
Another Pakistani official said the deployment emphasised that Saudi Arabia's internal security and economic prosperity are key interests for Islamabad, but that Pakistan would not do anything that could be perceived as taking sides in the regional rivalry between Tehran and Riyadh which has inflamed sectarian divisions across the Middle East.
Former Pakistani army chief Gen Raheel Sharif was selected last year by Riyadh as the potential commander of the Saudi-led alliance of Muslim-majority countries aimed at counter-terrorism. But this prompted concerns among politicians and within the army command that Pakistan was becoming too involved in an organisation that excluded Iran and Iraq, where the government is dominated by Shiites.
Up to a quarter of Pakistanis are also Shiite, and that proportion is reflected in the armed forces.
"You don't want to get involved in a conflict that is ultimately sectarian because that is going to undermine the unity of the Pakistan army," said Rifaat Hussain, an expert on Pakistan's relations with the GCC at the National University of Science and Technology in Islamabad.
Since then, debate has continued in Islamabad about whether to allow retired Gen Sharif to fill the role and what the parameters for any Pakistani troop involvement will be. Gen Sharif himself has reportedly placed conditions on his taking the position, including a role as mediator between Saudi Arabia and Iran.
If the latest discussed deployment of a Pakistani brigade to Saudi Arabia goes ahead, it would not be as part of the Islamic military alliance. But it is a sign of a marked improvement in ties between Pakistan and Arab Gulf states since the low point of 2015.
* Taimur Khan reported from Abu Dhabi