Iran's foreign minister Javad Zarif visits Pakistan amid escalating tensions with US

The purpose of the visit by Mohammad Javad Zarif, who held talks with his Pakistani counterpart, Shah Mehmood Qureshi, and also Prime Minister Imran Khan, was not made public.

But there has been speculation that Iran is looking to Islamabad and its close relationship with Riyadh to help de-escalate the situation.

Ahead of Zarif's arrival, Pakistan's foreign ministry called on "all sides to show restraint, as any miscalculated move, can transmute into a large-scale conflict."

Zarif has been criticized by name this week by Iran's supreme leader, Ayatollah Ali Khamenei, who named him and President Hassan Rouhani as failing to implement the leader's orders over Iran's 2015 nuclear deal with world powers.

Khamenei had claimed the deal had "numerous ambiguities and structural weaknesses" that could damage Iran.

Tensions have ratcheted up recently in the Mideast as the White House earlier this month sent an aircraft carrier and B-52 bombers to the region over a still-unexplained threat it perceived from Iran.

The crisis takes root in the steady unraveling of the nuclear deal, intended to keep Iran from obtaining a nuclear weapon. The accord promised economic incentives in exchange for restrictions on Tehran's nuclear activities.

The Trump administration pulled America out of the deal last year, and subsequently re-imposed and escalated US sanctions on Tehran - sending Iran's economy into freefall.

Khamenei's criticism of Zarif signaled a hard-line tilt in how the Islamic Republic will react going forward amid President Donald Trump's maximalist pressure campaign.

Iran declared earlier this month that the remaining signatories to the deal - Germany, France, Britain, China and Russia - have two months to develop a plan to shield Iran from American sanctions.

On Monday, Iran announced it had quadrupled its production capacity of low-enriched uranium, making it likely that Tehran will soon exceed the stockpile limitations set by the nuclear accord, which would escalate the situation further.

Several incidents have added to the crisis.

On Thursday, Saudi Arabia said Yemen's Iran-aligned rebels again targeted an airport near its southern border with a bomb-carrying drone. The Saudi military said it intercepted the drone, while the rebel Houthis said it struck a Patriot missile battery at the airport.

The Houthis have claimed three times in recent days to have targeted the airport, which also hosts a military base. It comes after the Houthis last week targeted a Saudi oil pipeline in a coordinated drone attack.

Pakistan was quick to condemn the attacks and promised Saudi Arabia, a staunch ally, its full support. The kingdom this week announced a $3.2 billion deferred oil and gas payment package for energy-strapped Islamabad.

Read more: Pakistan awards Saudi's crown prince 'Global Influential Figure' title

With neighbouring Iran, Pakistan walks a fine line and their relationship is sometimes prickly. Islamabad has little leverage with Washington, although relations between the two have improved since Pakistan expressed readiness to help move talks between the Afghan Taliban and Washington forward.

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