Ethiopian officials blamed the rebel Oromo Liberation Front (OLF) on Monday for a bomb that ripped through a train car, killing two people and injured nine others.

Spokesperson Zemedkun Tekle said the terror attack had all the hallmarks of the rebel group fighting for greater autonomy for the Oromo people. The bomb exploded at midday on Friday as the train neared the town of Adiquala, about 190km from the Djibouti border, heading for the provincial town Dire Dawa.

The rebels have been waging a guerrilla war against the current government since the early 1990s.

"The OLF is a terrorist group, nothing more, nothing less, because they are always attacking civilians," Zemedkun said. "They attack innocent people, the poor infrastructure of the country, the poor resources of the country. They represent no group, they are just a terrorist group."

He declined to reveal what evidence the government had for accusing the rebels other than saying it was similar to previous attacks by the group.

Hassan Shauffa, the deputy commissioner of the federal police, said investigators were at the scene and were searching for clues.

"An investigation team has gone to Dire Dawa," the deputy commission said. "What happened is quite clear. Some minor explosive was put in a bag and placed on the train."

The rebels claimed responsibility for a similar bombing along the same rail line in June 2002, which damaged a terminal building and one train carriage. In September last year a bomb that exploded at the Tigray hotel in Addis Ababa, killing three, was linked to the separatist group although it denied responsibility.

No one from the rebel group has commented on the latest bombing and the group was not immediately reachable for comment.

The blast comes amid tight security provided by the United States military in the Horn of Africa. US military experts began counter-terrorism training for Ethiopian troops in July at a military base near Dire Dawa. -- Sapa-AP