In an email to media, the militants dubbed the campaign “Operation Omari” in honour of Taleban founder Mullah Mohammad Omar, who died three years ago.
The militants added that in areas under their control, “mechanisms for good governance will be established so that our people can live a life of security and normalcy”. The insurgents control several rural districts and last year seized the northern city of Kunduz and held it for three days.
The Taleban said it would try to avoid killing civilians or destroying civilian infrastructure, and would carry out a “dialogue with our countrymen in the enemy ranks” to try to convince them to join the insurgency.
More than 11,000 civilians were killed or wounded in 2015, according to the UN.
The Taleban went through a period of infighting after Mullah Omar’s death became public last summer. Mullah Omar’s deputy, Mullah Akhtar Mansoor, had run the insurgency in his name and was elected as his successor by a small clique amid mistrust from the rank and file.
The dispute had little impact on the battlefield, however, where the Taleban have advanced on a number of fronts over the past year. And in recent months, Mansoor has consolidated power, bringing several one-time rivals back into the fold.
The Taleban said around 20 fighters with a local Islamic State affiliate in the eastern Nangarhar province had pledged their support for Mansoor. It would be the first time IS militants, many of whom are disgruntled former Taleban members, have joined the Taleban in the province, which has seen heavy fighting between the rival groups.
The fighting subsides in much of Afghanistan during the winter, when snow and inclement weather descends on the mountainous border with Pakistan.