Myanmar Buddhist monk Wirathu speaks at a rally against constitutional change in Yangon. File picture: Ann Wang/Reuters

Yangon - A judge in Myanmar has issued an arrest warrant for Wirathu, a firebrand Buddhist monk who for years has been the face of the country's ultranationalist movement and has given inflammatory sermons against the government of Aung San Suu Kyi.

The warrant was issued on Tuesday, after an official from Myanmar's General Administration Department filed sedition charges against the monk, the local news site Myanmar Now reported on Wednesday.

The contents of the lawsuit remain unknown. Sedition is defined by Myanmar's penal code as an attempt "to bring into hatred or contempt, or excite or attempt to excite disaffection towards, the government." It carries a maximum sentence of life in prison.

Earlier this month, Wirathu led a rally against attempts by Suu Kyi's civilian government to amend the country's constitution, which would limit the military's political power. During a speech, he accused her of being influenced by and "sleeping with" foreigners.

Wirathu was previously jailed by Myanmar's military junta in 2003. When he was released in 2012, he began delivering anti-Muslim speeches throughout the country. That year, riots erupted in Rakhine state that led to the displacement of over 100,000 Rohingya to internment camps, where they remain to this day.

Facebook de-platformed Wirathu in January 2018, and he was banned from entering Thailand last month.

Earlier this month, after hearing that the Ministry of Religious Affairs was preparing a defamation lawsuit against him, Wirathu posted a defiant video on the Russian social media platform VK saying: "I give speeches without the fear of handcuffs and prisons."