PARIS (Reuters) - Al Qaeda in the Islamic Maghreb's (AQIM) claim of responsibility for the killing of two French journalists in northern Mali last week is plausible, French Foreign Minister Laurent Fabius said on Thursday.

The Mauritanian news website Sahara Medias said it received a claim of responsibility from al Qaeda's regional wing for the killing of the two journalists, who worked for Radio France International (RFI) when they were kidnapped in the northern city of Kidal.

A spokesman for Abdelkrim al-Targui, a senior AQIM regional commander, told Sahara Medias the killings were just a small part of the price President Francois Hollande and his people would pay for a January military intervention in Mali.

"We are checking, but it (the claim) seems plausible," Fabius told I>Tele television.

French and Malian troops launched the military operation to clear Islamist militants from the north of the country who were threatening to invade the capital of Bamako, an intervention that France described as largely successful.

Yet pockets of militants remain active in parts of the country including the desert city of Kidal, a stronghold of Tuarag separatist rebels where France plans to increase its military presence by 150 troops.

Despite the killings and reports of continuing militant activity, Fabius repeated that Paris would not delay a planned drawdown of its troop presence in Mali from 3,200 to 1,000, scheduled for February.

That number is to be supplemented by some 380 troops from the Netherlands to boost the U.N. mission in Mali, known as MINUSMA, which will eventually number 12,000.

Asked whether France planned to maintain troops in Mali for years to help maintain stability, Fabius added: "That is not our intention."

The killings follow the freeing of four other French hostages, employees of French energy firm Areva who had been held in the Sahel region for three years.

(Reporting By Nicholas Vinocur; editing by Mark John)