The health condition of BNP senior joint secretary general Ruhul Kabir Rizvi Ahmed has deteriorated further.
He has been undergoing treatment at Square Hospital in the capital after being infected with coronavirus.
Arifur Rahman Tushar, a close aid of Rizvi, confirmed the matter.
Rizvi was given oxygen support as his oxygen level dropped, Tushar said.
Earlier, his third coronavirus virus test report came positive on Wednesday.
Family of the leader requested the countrymen to pray for his quick recovery.
BDST: 1219 HRS, APR 01, 2021