The letter went viral after a mischievous user shared it on social media.

Although the letter bore numerous signs of a fake document, many Kenyans fell into the trap and re-shared to various social media platforms.

It did not take long before the Nairobi county boss responded through his Facebook page, warning that he would remain in office until his term ends in 2022.

"Whoever is circulating this malicious nonsense should desist with immediate effect. I'm the elected Governor of Nairobi until the end of my term. Buree kabisaa," Sonko stated.

Fake news has become a new propaganda weapon that is increasingly being used in political communications.

President Uhuru Kenyatta recently enacted the Computer Misuse and Cybercrimes bill into law, making publication and dissemination of fake news a crime.