Tigrean rebels say they have seized an important garrison town in what Ethiopia's government describes as a major offensive that has cut the capital's access to the north.

"The nation has never faced such a critical and dangerous situation," the ruling Council of State said in a communique.The guerrillas, who have been fighting since 1975 for greater autonomy for their home province of Tigre, said Tuesday they captured the town of Bahr Dar the previous day.