U Win Htein, patron of Myanmar's National League for Democracy (NLD), was arrested late Thursday, an official from the Myanmar Police Force told, Trend reports citing Xinhua.
The 80-year-old patron, who is believed to be a trusted confidant of the party's chair Aung San Suu Kyi, was taken to a district police station in Nay Pyi Taw, soon after his arrival in Yangon from Nay Pyi Taw on Thursday, Kyi Toe, a member of the party's information committee, wrote on his social media account earlier.
Meanwhile, President U Win Myint and State Counsellor Aung San Suu Kyi were remanded in custody for violating the National Disaster Management Law and Import-Export Law until Feb. 15, according to a senior military official.
The president and state counsellor were detained by the military, along with other NLD officials early Monday.
The NLD recently posted a statement on its social media page demanding the military release the detained leaders, acknowledge the results of 2020 general elections and stop any disturbances which are hindering the process of convening the third parliamentary session.
Myanmar declared a one-year state of emergency and the state power was handed over to the Commander-in-Chief of Defence Services, according to the military statement.