BAMAKO (Reuters) - Mali's interim president plans to appoint a new prime minister within 24 hours to replace Cheick Modibo Diarra, who was forced to resign on Tuesday following his arrest by soldiers who staged a coup in March.

Diarra's arrest underscored the military's continuing grip to power in Mali and could complicate international efforts to help push Islamists out of the north of the country.

In a prepared speech he is expected to read on national television later on Tuesday, President Diouncounda Traore said he had accepted the resignation of the prime minister and the government.

"The resignation was formally handed to me in writing, I have taken note and have accepted it," Traore was to say in the speech, of which Reuters has seen a copy.

"Within the next 24 hours, Mali will know its new prime minister and a government will follow by the end of the week," Traore added in the prepared remarks.

(Reporting by Adama Diarra; Writing by Bate Felix; Editing by Michael Roddy)