Exclusive-US, Iran leave door open to dialogue after tense Islamabad talks

By Ariba Shahid, Parisa Hafezi, Saad Sayeed, Asif Shahzad and Humeyra Pamuk

ISLAMABAD/DUBAI/WASHINGTON April 13 (Reuters) – After a sleepless and at times tense night in Islamabad, Iranian and U.S. officials ended their highest-level talks in…