FILE PHOTO: People gather at Doha Corniche as they celebrate Qatar's National Day December 18, 2015. REUTERS/Naseem Zeitoon/File Photo

DUBAI (Reuters) - Three Gulf Arab states and Egypt said they will not attend a global meeting of parliamentarians due to be held in Doha from Saturday because Qatar has not changed the kind of behavior which made them sever ties two years ago.

Saudi Arabia, the United Arab Emirates, Bahrain and non-Gulf Cooperation Council (GCC) member Egypt cut diplomatic, transport and trade ties with Qatar in 2017, accusing it of supporting terrorism and their regional foe Iran - something Doha denies.

The quartet plans to boycott an Inter-Parliamentary Union (IPU) annual meeting in Doha April from 6-10, they said in a statement carried on UAE state news agency WAM late on Thursday. The IPU is a global organization of national parliaments that promotes democracy.

They will not attend because Qatar “has not responded to the just demands of the four countries and has continued its supportive policy for extremism, terrorism and interference in the affairs of the countries of the region,” it said.

Gas-rich Qatar says the boycott is aimed at undermining its sovereignty. It has started charting a course away from its Gulf neighbors, including forging new trade partnerships, strengthening ties with Turkey and quitting OPEC.

Those moves have deepened expectations that the dispute will not be resolved quickly, unnerving the United States, the main Western ally of the six-nation Gulf Cooperation Council which sees the rift as a threat to efforts to contain Iran.

The United States, which has military bases in both Qatar and some of the countries lined up against it, is trying to mediate the feud.