At least 23 Afghan security forces were killed in a series of Taliban attacks across the country, officials said Wednesday, despite winter snowfall that usually leads to a lull in violence.

The assaults targeted vulnerable checkpoints in at least three northern provinces. In Balkh, militants stormed a checkpoint early Wednesday and killed at least seven police officers, according to provincial police chief Ajmal Fayez.

He said reinforcements had been dispatched to the post, which is located on the strategic highway connecting Balkh to neighbouring Jawezjan province.

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A Taliban spokesperson claimed that 11 police offices died in the attack, but Afzal Hadid — a member of the provincial council — put the death toll at nine, adding that four others were missing.

"We are not sure whether these four police [officers] helped the Taliban in the attack or have been captured by them," he said.

Separate assaults by the Taliban killed at least nine members of Afghan security forces in northeastern Kunduz, and seven in neighbouring Takhar province, officials said.

The provincial spokesperson for Takhar said that at least 11 militants were killed as they attacked a security checkpoint in Darqad, close to the border with Tajikistan.