Taliban spokesman Zabihullah Mujahid announced the launch of the offensive in an email statement that boasted Taliban control over more than half of the country, referencing a February report issued by Washington's special inspector general for Afghan reconstruction.
That report said that the Afghan government had control or influence over only 52 per cent of Afghanistan's 407 districts last year, down from 63.4 per cent previously.
The Taliban dubbed this year's offensive "Operation Mansouri," named for the Taliban leader killed last year in a US drone strike.
Attempts to find a peaceful end to Afghanistan's protracted war have been relentlessly unsuccessful.
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On the political side, Mujahid said the Taliban were going to begin building institutions in areas under their control, establishing what he called "social justice and development" mechanisms.
He didn't offer specifics nor did he indicate whether this was an indication that the Taliban would step up their brand of justice that during their rule included the chopping off of hands for those convicted of theft and public executions.
In the latest attack, the Taliban disguised as Afghan army soldiers slipped into the compound of the 209 Corps in northern Afghanistan's Balkh province. While two militants exploded their suicide vests, the others opened fire on scores of soldiers.
As well as the Taliban, Afghanistan is also battling an emerging local Islamic State affiliate known as Islamic State in Khorasan.