Twitter is suspended “indefinitely” in Nigeria, “for the persistent use of the platform for activities that are capable of undermining Nigeria’s corporate existence,” according to a statement (threaded on Twitter) from the country’s minister of information and culture. The move comes days after the platform removed a threatening tweet by president Muhammadu Buhari which Twitter said violated its “abusive behavior” policy.

On Saturday, the office of Nigeria’s attorney general and ministry of justice said it would arrest and prosecute anyone who tried to get around the block, CNN reported, and directed government agencies to cooperate with prosecutors “to ensure the speedy prosecution of offenders without any further delay.” Several news reports said people within Nigeria were using VPNs to try to avoid the ban and continue using Twitter.

In Buhari’s deleted tweet, he suggested he would punish secessionists. “Many of those misbehaving today are too young to be aware of the destruction and loss of lives that occurred during the Biafra war,” he wrote. “Those of us in the fields for 30 months, who went through the war, will treat them in the language they understand.” Buhari was a major general during the Biafra war, which left more than a million people dead.

Twitter’s Public Policy team said in a statement Saturday it was “deeply concerned” and would work to restore access in Nigeria. Reuters reported Saturday that Twitter’s website was not accessible on some of Nigeria’s mobile carriers, but appeared to be working sporadically on other carriers in Lagos and Abuja, two of the country’s biggest cities.

“Suspending Twitter in Nigeria is just one more way of stating that people’s rights do not matter just what the State wants,” Osai Ojigho, director of Amnesty International in Nigeria tweeted. “This is a dangerous precedent and must be called out for what it is.” Amnesty called on Nigerian authorities to immediately reverse the suspension, “and other plans to gag the media, repress civic space, and undermine Nigerians’ human rights.”

In April, Twitter opened its first office in Africa in Ghana, which some in Nigeria considered a snub. In its announcement, Twitter cited Ghana’s support of free speech, online freedom and the Open Internet as the reasons for its decision. Nigeria’s information minister said at the time that Twitter’s decision not to locate its Africa offices in Nigeria was due to misrepresentation of the country by the media.

According to a 2020 report from Amnesty International, Nigerian authorities “used repressive laws to harass, intimidate, arrest and detain human rights defenders, activists, media workers and perceived critics. Non-state actors also subjected journalists to intimidation, harassment and beatings.”

Update June 5th, 4:44PM ET: Adds that the Nigerian government plans to arrest and prosecute people who try to get around the Twitter ban.