Although French paramilitary commandos showed considerable skill in rescuing passengers and crew this week from an airliner hijacked by Islamic militants, the deadly confrontation may be only the first chapter in a European phase of the bloody civil war in Algeria.

The commandos clearly had little choice but to storm the Air France plane at the airport in Marseille despite the risk to 170 hostages. The four hijackers had already murdered three passengers, were threatening more killings and apparently planned to blow up the airliner over Paris.But the use of French commandos on French soil inevitably brought Paris more directly into Algeria's civil war, despite official government pronouncements that the French are not involved. Such protestations are not likely to convince Muslim extremists who can be expected to expand their war of terrorism to French soil.

Algeria's long historical ties to France, including 114 years as a colony, have left a close relationship despite a cruel eight-year war of in- dependence that drove out the French in 1962. More than 2.5 million Algerians live in France, most as law-abiding citizens. But that large population makes it difficult to find and control terrorists who may be hiding in their midst.

Some 10,000 expatriate French citizens lived in Algeria when the Algerian government's war with the fundamentalists fighting began. Only about 1,000 remain. France is Algeria's main supplier of goods and provides crucial technical support for the country's oil industry.

The civil war broke out in 1992 after the government canceled election results when Muslim fundamentalists appeared to be on the way to winning control of parliament. That was hardly the right thing to do, but it was a tough choice. The fundamentalists had vowed to turn the state into a militant theocracy if they gained political control. Further free elections might have been a casualty in any case.

Some of the more extreme Muslim groups have sought to isolate the Algerian regime my murdering foreigners in Algeria. After the hijacking this week, four Catholic priests - three French and a Belgian - were shot to death in their rectory about 60 miles from the Algerian capital.

The war has cost at least 11,000 lives to date, a figure some say is only a third of the real casualties.

The United States is concerned about the Algerian mess because it has wide international consequences. If the extremists topple the government - and some experts think that is inevitable - their fundamentalist doctrine may be exported to neighboring countries and threaten Egypt, which already has a problem with radical Islamic movements.

Algeria's oil and gas are increasingly important to Europe. Spain depends on Algeria for most of its natural gas. Algeria has the potential to become another trouble spot like Iran.

Washington is pressuring Paris to negotiate with the Muslim fundamentalists to end the bloodshed, a move that has precipitated a behind-the-scenes diplomatic strain between France and the Clinton administration. The French say the fundamentalists refuse to compromise.

Yet negotiation makes the only sense. If France waits until terroristic war breaks out on its own soil, any settlement will become extremely difficult. Only one thing is certain at this point: The world - and France in particular - has not heard the last of the Muslim extremists in Algeria.