Omani Telecommunications Regulator says Clubhouse app and similar communication applications "must obtain a permit from the authority".
Oman has blocked US audio app Clubhouse because it did not have the right permit, authorities said, but some activists described the move as a further erosion of freedom of expression in the Gulf state.
The government did not respond immediately to a request for comment, but the telecoms regulator told WAF news website that the application was blocked due to a "lack of proper authorisation".
"Similar communication applications must obtain a permit from the authority," the Omani Telecommunications Regulatory Authority said.
Oman_blocks_Clubhouse was trending on social media in Oman on Sunday. Many Omanis shared screenshots of the app showing "error message".
Popular in Arab countries
"The government of Oman takes the authoritarian government of China as a role model and bans ... Clubhouse which has been used by Omanis as a space to express their opinions freely without government censorship," the Omani Association For Human Rights said in a statement.
Access to Clubhouse was blocked in China last month.
Launched in early 2020, the San Francisco-based app saw global user numbers soar after Tesla CEO Elon Musk and Robinhood CEO Vlad Tenev held a surprise discussion on the platform.
The app has been popular in Arab countries where media is directly controlled by governments and commentators run the risk of being imprisoned for critical opinions.
Clubhouse has faced criticism elsewhere over reports of misogyny, anti-Semitism and Covid-19 misinformation on the platform despite rules against racism, hate speech, abuse and false information.
The app has said it is investing in tools to detect and prevent abuse as well as features for users, who can set rules for their rooms, to moderate conversations.
"I hope that the suspension of the Clubhouse app in Oman is a result of technical issues and not a formal ban," tweeted Omani writer Zakaria al-Muharrmi.
"Preventing people from speaking and listening to others does not protect societies, but rather increases tensions and pushes them into the abyss of chaos and confrontation."