India, April 20 -- Pakistan appears to be preparing for high-stakes talks that may ultimately not take place, even as uncertainty deepens around the next phase of US-Iran negotiations.

In Islamabad, security measures have already been ramped up. The capital is effectively in lockdown in the red zone and several surrounding areas, reported news agency Reuters, adding that the roads are sealed and movement is tightly controlled. Track US-Iran war live updates.

The preparations suggest Pakistan, which has been acting as the main mediator, is bracing for another round of diplomacy as the temporary ceasefire deadline ends on April 22.

Islamabad municipal authorities have halted public transport and heavy-goods traffic across the city, the r...