KINSHASA, Congo (AP) _ A Congolese military plane was hit by rebel gunfire and exploded on the runway after making an emergency landing, killing 12 people, a military official said Tuesday.

The incident fueled concerns that a July 10 peace accord between the Congolese government and the rebels could break down.

The Russian-built plane was swooping in to bomb a rebel target Thursday when it was struck by rebel groundfire, said the official, who spoke on condition of anonymity.

The plane immediately returned to the airport in the town of Mbandaka in the northern part of the country.

A number of passengers, including Maj. Gen. Faustin Munene, the head of Congo's air force, escaped from the plane before it exploded. But 12 others did not _ including two Ukrainian pilots and two Congolese.

No information was available on the other victims. Many of the pilots flying for the Congolese government are believed to be Ukrainian and Russian mercenaries.

It was not clear how many people had escaped the blast, which also damaged the airport.

While the July peace accord officially remains in affect in Congo, it has been in increasing jeopardy in recent days. Last week, each side accused the other violating of the agreement and vowed to return to war if one more shot was fired.

On Saturday, President Laurent Kabila's government imposed an overnight curfew in the western half of the country it controls, declaring that rebels were preparing for a major assault.

The war, which began in August 1998, drew in forces from at least five other countries. Zimbabwe, Namibia and Angola have been propping up Kabila's regime, while Uganda and Rwanda _ both of which supported Kabila in his earlier war against former President Mobutu Sese Seko Mobutu _ have been supporting the rebels trying to overthrow him.

The Congolese rebels now control much of the country's north and east.