BNP Chairperson Khaleda Zia is undergoing treatment under close supervision for chest infections.
She was admitted to Evercare Hospital in the capital on Sunday night after developing the infections, which have affected her heart and lungs, according to her medical board.
While updating reporters about Khaleda's health yesterday, her personal physician Prof AZM Zahid Hossain, also a BNP Standing Committee member, said the former prime minister has urged people to pray for her speedy recovery.
Khaleda, 80, has long been suffering from multiple health complications, including liver cirrhosis.
Prof FM Siddiqui, a member of the medical board, said several of her health problems flared up simultaneously on Sunday.
"She has a chest infection, which has affected her heart and lungs at the same time, causing respiratory distress. We have carried out urgent tests. Based on the reports received so far, she has been started on antibiotics," Prof Siddiqui added.
In a message sent to The Daily Star around 9:30pm, another doctor from the medical board said, "Madam [Khaleda] has pneumonia. Treatment is ongoing. If there is no improvement, she may be taken to the CCU soon. Along with pneumonia, some other complications have arisen.
"Because of her age, she cannot receive all treatment at the same time even if we want to .... The doctors will keep her under close observation for the next 24 hours."
Since returning home from London on May 6 after advanced medical care, Khaleda has been undergoing regular check-ups at Evercare Hospital.
Her family members, including Tarique Rahman and his wife Zubaida Rahman, are in close contact with her doctors.