The death toll from a suicide attack on Afghan security forces has soared to 68, officials said Wednesday, as violence flares across the country ahead of elections and a key Islamic holy day, Muharram.

The bombing on Tuesday in the eastern province of Nangarhar was the latest in a wave of deadly insurgent attacks which has claimed the lives of hundreds of civilians and security forces across Afghanistan, AFP reported.

The blast wounded another 165 people, provincial governor spokesman Ataullah Khogyani said.

There has been no claim of responsibility for the attack. The Nangarhar health department confirmed the toll, the AFP report said.

Scores of demonstrators had blocked the highway between the provincial capital of Jalalabad and a major Pakistan border crossing in protest over the appointment of a local police chief when the suicide bomber blew himself up.

The dead and wounded were rushed to several hospitals in the back of pickup trucks and ambulances, overwhelming doctors and nurses as they struggled to cope with the huge number of casualties.

It was the deadliest attack since an ambulance packed with explosives detonated in a crowded street in the heart of Kabul in January, killing more than 100 people, mostly civilians. That bombing was claimed by the Taliban.

Violence across the country has intensified in recent weeks as the Taliban make gains on the battlefield.

It comes as Afghanistan enters a typically violent period of the year — the holy month of Muharram, which began on Tuesday.

Ashura, the most important Shiite observance, falls on the 10th day of Muharram and is often marred by deadly attacks.