President Maithripala Sirisena, addressing a Joint Opposition rally near Parliament, said he first offered premiership to Speaker Karu Jayasuriya and UNP Deputy Leader Sajith Premadasa.
"Both of them turned down the opportunity saying they could not go against the party leader. Then, I decided to appoint a man who could topple Ranil and his government," Sirisena said.
"When Ranil was in power, important decisions of the government were made by a gang of butterflies," Sirisena said passing a sexual innuendo at his erstwhile colleague, Wickremesinghe.
"I couldn't agree with his butterfly rule and that was why I decided to think of other alternatives," he added.
Sirisena also said he consulted legal experts before removing Wickremesinghe and the entire process was handled in accordance with the constitution.
Addressing the rally, Sirisena said he would not backtrack on his decision, despite challenges and obstacles.
He also said his party had already secured the majority in Parliament.