France will start withdrawing troops from Mali as of April, French President Francois Hollande said here Wednesday. During a visit to Warsaw, Hollande also said \"terrorist leaders\" had been killed in an operation against Islamist rebels in a northern Mali mountain range. But he did not provide details on the identities of those killed. The Elysee Palace on Wednesday said a fourth French soldier had been killed during clashes with Islamist insurgents in Mali.