A demand by Saudi Arabia and three other Arab nations for Qatar to close down its al-Jazeera TV channel is an "unacceptable attack" on the right to freedoms of expression and opinion, the United Nations human rights chief said on Friday.

Saudi Arabia, the United Arab Emirates, Bahrain and Egypt imposed a boycott on Qatar three weeks ago, accusing it of backing militants, then issued an ultimatum, including demands it shut down a Turkish military base in Doha, shutting Al Jazeera and curbing ties with Iran.

U.N. High Commissioner Zeid Ra'ad al-Hussein is "extremely concerned by the demand that Qatar close down the Al Jazeera network, as well as other affiliated media outlets", his spokesman Rupert Colville told a news briefing.

"Whether or not you watch it, like it, or agree with its editorial standpoints, Al Jazeera’s Arabic and English channels are legitimate, and have many millions of viewers. The demand that they be summarily closed down is, in our view, an unacceptable attack on the right to freedom of expression and opinion," Colville said.