Firefighters from France and England extinguished a blaze Friday in a tunnel under the English Channel, but undersea train traffic remained suspended for a second day, officials said.

Firefighters were still putting out some small localized flames in the tunnel, Gerard Gavory, deputy head of the Calais regional administration, told reporters.

The fire broke out Thursday afternoon on a truck aboard a 30-car shuttle train traveling from England to France, injuring 14 people in one of the most serious incidents in the history of the 30-mile tunnel, which opened to passengers in 1994.

French Transportation Minister Dominique Bussereau said Friday that the fire "likely resembles something accidental," without elaborating. Jacques Gounon, chief executive of Eurotunnel, which operates the tunnel, said he had no reason to believe the fire could have been "criminal."

Bussereau said he was "incapable of saying today when the traffic could resume" in the tunnel. "First we have to put out the fire, we have to inspect what happened, ventilate the tunnel," Bussereau said on Europe-1 radio.

Gounon said one of the three passages that make up the Channel Tunnel — the undamaged southern passage that normally carries France-to-England traffic — could reopen as soon as Friday evening.

"We must verify that all fire detection systems function well. We will take our time," he said.

Gavory said firefighters were starting to cool down and ventilate the tunnel to ensure that flames didn't reignite. Because of the high temperatures, firefighters were spending no more than 15 minutes at a time inside the tunnel, Gounon said.

The Channel Tunnel is composed of three tunnels, each 130 feet beneath the sea bed. One tunnel carries shuttles, Eurostar passenger trains and freight traffic from France to England, while another runs in the opposite direction.

The pair are connected to a central service tunnel, used for maintenance and emergency access. The central tunnel is kept under a higher pressure than the train tunnels it flanks to keep out smoke in case of fire.

Gounon said the damaged part of the northern tunnel would remain closed "for several weeks."

Eurotunnel, which has been plagued by financial troubles and was heavily burdened by debt before reaching a restructuring deal last year, assured investors in a statement Friday that any financial impact of the accident "will be limited."

Eurotunnel shares dropped 4 percent Thursday after the fire broke out and fell further Friday morning before climbing back up to $12.58 at midday.

The launch of the Eurostar trains dramatically changed both passenger and freight travel between Britain and the European continent. Some 26,000 people a day travel the tunnel on average, according to latest traffic figures.

The huge lines of trucks that built up on the English side of the tunnel had lessened Friday as police told motorists to avoid the area. Kent Police said an emergency procedure dubbed "Operation Stack" — in which parts of a major highway are turned into a giant parking lot for trucks — was still in place.