In this Oct 30, 2017, photo, French President Emmanuel Macron, right, flanked by French Interior Minister Gerard Collomb, addresses the media after signing a counterterrorism law, at the Elysee Palace, in Paris, France. (CHRISTOPHE ENA / AP)

PARIS — French Prime Minister Edouard Philippe has assumed responsibility for France's domestic security after the interior minister resigned in an apparent act of defiance toward President Emmanuel Macron.

Gerard Collomb, 71, was one of Macron's closest political allies

In a cold handover ceremony Wednesday, Philippe said his main focus would be to ensure "the highest security level" in the country.

Philippe is in charge until Gerard Collomb's successor is appointed.

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In this July 31, 2018, photo, French Prime Minister Edouard Philippe delivers his speech during a no confidence session at the National Assembly in Paris. (MICHEL EULER / AP)

Macron accepted Collomb's resignation late Tuesday, after initially refusing it the previous day. Collomb insisted he wanted to leave to be able to run for mayor of the city of Lyon in 2020.

Collomb, 71, was one of Macron's closest political allies. His decision comes amid a string of bad news events for the French president, who has reached record low popularity in polls since his election in May 2017.