Image copyright EPA Image caption The death toll from Tuesday's suicide bombing soared overnight

A suicide bombing in east Afghanistan has killed at least 68 people, officials say, in one of the deadliest insurgent attacks in recent months.

The bomber struck in a crowd of people protesting against a local police chief in Nangarhar province near Pakistan.

The death toll from Tuesday's blast soared overnight. Another 165 people were injured - local hospitals struggled to cope with the casualties.

Hundreds have died in a wave of recent attacks. Elections are due in October.

No group has said it carried out the suicide bombing in the crowd of protesters in Nangarhar's Momand Dara district, but Islamic State militants are active in the province.

Earlier, five people were injured in two bomb attacks near a school in the same province.

Officials are warning that more attacks are likely with campaign rallies due to be held ahead of parliamentary elections. The violence has led some to question whether the poll can be held on 20 October as scheduled.

Image copyright EPA Image caption Schools in Nangarhar were also targeted in blasts on Tuesday

The violence follows recent diplomatic efforts to end the lengthy war with the Taliban.

Dozens of Afghan security personnel and Taliban fighters were killed in battles across four northern provinces earlier this week.

Government forces have suffered several setbacks in recent weeks in their battles against the Taliban.

In August, militants also briefly seized the major city of Ghazni, sitting on the main highway between the capital Kabul and the south of the country.

The renewed fighting has dampened the prospect of diplomatic progress ending the war.

Earlier this year, hopes were raised after an unprecedented three-day ceasefire during Eid celebrations was largely respected by both sides, and Taliban officials secretly met a senior US diplomat in Qatar in July.