The countries have long worried about being sucked into regional war as they juggle relations with Washington, their security guarantor, while seeking to improve ties with Tehran.

The US embassy in Qatar has also lifted its shelter-in-place order and said operations will resume as normal on Tuesday.

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.