(CNN) -- Saudi Arabia, the United Arab Emirates and Bahrain announced Wednesday the withdrawal of their ambassadors from Qatar because Doha had not implemented an agreement among Gulf Arab countries not to interfere in each others' internal affairs.
The three countries, which are all part of the Gulf Cooperation Council (GCC) along with Qatar, announced the unprecedented move in a joint statement.
They said GCC members had signed a deal November 23 that included "a security agreement and a commitment to the principles that ensure non-interference in the internal affairs of any of the GCC countries, either directly or indirectly, and not to support any activity that would threaten the security and stability of any of the GCC countries from organizations or individuals, including support for hostile media."
GCC foreign ministers met in Riyadh Tuesday to try to persuade Qatar to implement the agreement, the statement said.
"Saudi Arabia, UAE and Bahrain hoped that the agreement will be implemented, however, after more than three months after the signing of the agreement, Saudi Arabia, UAE and Bahrain feel that the State of Qatar did not take the necessary actions to put it into practice," a statement on the Saudi Foreign Ministry Facebook page said.
"Therefore Saudi Arabia, UAE and Bahrain regret to announce that they will take what they deem to be the appropriate steps to protect the security and stability of their nations by withdrawing their ambassadors from Qatar."
Qatar expressed "regret and surprise" at the decision and said it would not reciprocate with the same move, a cabinet statement published on the state Qatar News Agency said.
It said it would remain committed to "preserving and protecting the security and stability" of the GCC countries.
Tensions between Qatar and the rest of the GCC have increased in recent years.
Wednesday's announcement is the clearest sign yet of a rift between Gulf Arab nations and Qatar, a perceived supporter of Islamist groups such as the Muslim Brotherhood in Egypt and elsewhere in the Middle East -- which are viewed with suspicion or outright hostility by some fellow GCC members. Qatar denounced last year's ouster of Egypt's Islamist President Mohamed Morsy, who hails from the Brotherhood.
The GCC, formed in 1981, consists of Saudi Arabia, Qatar, Kuwait, Bahrain, the United Arab Emirates and Oman.