Bangladesh, April 17 -- Washington is intensifying efforts to revive diplomacy with Tehran, with a second round of talks expected as early as next week and Pakistan's capital Islamabad emerging as the likely venue, officials said, as multiple fronts of the widening regional crisis show signs of cautious engagement.

US President Donald Trump said negotiations with Iran could resume "over the next two days," following an initial round of talks in Pakistan last weekend that ended without a deal after 21 hours of discussions. Despite the outcome, the White House signaled optimism.

A White House spokesperson said there was "a real opportunity to move forward," adding that future talks were likely to be held again in Islamabad. Pakistan's For...