Amid a background of political upheavals, an aide to Anwar Ibrahim has described as "fake" a purported letter of undertaking that pledged the PKR president's support for Prime Minister Muhyiddin Yassin.

A copy of the purported letter was shared in the PKR official WhatsApp group by Anwar's press-secretary Tunku Nashrul Tunku Ubaidah.

"Responding to media questions on this matter...