Bahrain's long-serving prime minister has called Qatar's emir to mark the start of the holy month of Ramadan in a rare contact between Doha and the countries boycotting it.

Bahrain's state-run news agency acknowledged the call between Prince Khalifa bin Salman Al Khalifa and Qatar's emir, Sheikh Tamim bin Hamad Al Thani, in a report early Tuesday.

It described the call as "restricted" to Ramadan greetings.

However, the island nation of Bahrain off the coast of Saudi Arabia has served as a stalking horse for Gulf Arab nations in warming ties to Israel.

Bahrain, Egypt, the United Arab Emirates and Saudi Arabia have boycotted Doha over a political dispute since June 2017. On Monday, the UAE released a Qatari naval vessel and four sailors it seized nearly a week earlier.