Nigeria's government announced on Friday it was suspending Twitter operations because the platform was being used for activities "capable of undermining Nigeria's corporate existence."
Twitter was still working in Africa's most populous country soon after Friday's statement, which triggered immediate criticism from rights groups and analysts about freedom of expression.
The information ministry said the government had "suspended, indefinitely" Twitter in Nigeria two days after the social media giant deleted a remark on President Muhammadu Buhari's official account for breaking regulations.
When asked about the decision, ministry special assistant Segun Adeyemi told AFP: "I can't answer technicalities… operations will be suspended indefinitely."
The ministry also announced the suspension on its own Twitter account though it gave no details on when the decision would take effect.
"The announcement made by the Nigerian Government that they have suspended Twitter's operations in Nigeria is deeply concerning," the company said in a statement.
"We're investigating and will provide updates when we know more."
Twitter had on Wednesday deleted a remark on Buhari's account for violating its rules, after he referred to the country's civil war in a warning about recent unrest in the southeast.
The 78-year-old president, a former general, referred to those "misbehaving" in recent violence in the southeast, where officials blame separatists for attacks on police and election offices.
Minister of Information Lai Mohammed on Wednesday accused Twitter of ignoring violent messages from a separatist leader and also referred to Twitter CEO Jack Dorsey's support for the #EndSARS protests last year in Nigeria against police brutality.
Rights group Amnesty International called for Nigeria to immediately reverse the "unlawful suspension."
"This is the height of muzzling the freedom of expression that can only happen in dictatorships," Bulama Bukarti, an analyst at the Tony Blair Institute for Global Change, said on Twitter after the announcement.
"It will go down in history as one Buhari's biggest mistakes and PR disasters."
Nigeria in 2019 had announced it would tighten regulations on social media to fight fake news and disinformation, but the proposal sparked concerns over freedom of expression.
Several countries including China and Turkey have come under fire for putting restrictions on social media platforms like Twitter.
Twitter in February condemned Myanmar's move to block access to its platform as part of a crackdown on social media, days after a coup that saw Aung San Suu Kyi and other civilian leaders jailed.
