With the ceasefire due to expire midweek, Pakistan has intensified diplomatic contacts with both Washington and Tehran.

The U.S. Navy on Sunday fired on and seized an Iranian-flagged cargo ship as part of its blockade of Iran-linked vessels in the Strait of Hormuz.

A U.S. seizure of an Iranian cargo ship and reports of vessels coming under fire in the Gulf have pushed a fragile ceasefire with Tehran to the brink.