An RAF transport aircraft loaded with French armoured vehicles has touched down in conflict-stricken Mali.
French forces have been carrying out air attacks on al Qaeda-backed rebels in the West African state in recent days.
The UK has offered two C-17 Globemaster transport planes to help out, but the Foreign Office insisted there are no plans to deploy British ground forces.
The Mali government appealed for France’s help after Islamist rebels began moving south at the end of last week.
Hundreds of French troops were deployed to the country at the weekend after the rebels overran the strategically important town of Konna – about halfway between Mali’s northern and southern borders – on Thursday.
France’s ambassador to the UN says thousands of African troops are expected in Mali, to support local and French forces in their fight against the rebels.
The first of the two giant RAF transport aircraft took off from Paris on Monday and landed in Mali with supplies for French forces.
A second C-17 is expected to leave soon after encountering what was described as a “minor technical fault” in the French capital.
Foreign Office Minister Mark Simmonds said David Cameron had offered only limited back-up support to French President Francois Hollande.
“The Prime Minister has made categorically clear that the initial supporting deployment will be for a period of one week,” he told the Commons.
“He has also made clear that there will be no combat troops from the UK involved and we have no plans to provide more military assistance.”
The US is providing intelligence-gathering assistance to the French in their assault, Defence Secretary Leon Panetta said.
EU foreign ministers are to hold an extraordinary meeting this week, probably on Thursday, to discuss the situation.
On Sunday, French forces forced back Islamists from the strategic town of Konna.
There had been fears that if their advance was not halted, they could have carried on all the way to the capital Bamako in the south.
Up to 60 Islamists are reported to have been killed in air assaults on Sunday, which were centred around Gao and Kidal.
Despite the French successes, Islamist forces still hold a huge swathe of the north of the country.