By Andrew Mills, Parisa Hafezi and Alexander Cornwell DOHA/ISTANBUL/TEL AVIV (Reuters) -Explosions were heard over Qatar's capital Doha on Monday, a Reuters witness reported, shortly after a Western diplomat said there had been a credible Iranian threat against the U.

Amid rising tensions after US strikes on Iranian nuclear sites, Iran claimed attacks on Al Udeid Air Base in Qatar, following airspace closure in Doha.

Texts from Northwestern University in Qatar started hours before the missiles began firing, alerting students to go to their homes.