The violence remains unabated even as American diplomats push to persuade the group to join formal negotiations. Led by Zalmay Khalilzad, a special envoy for Afghan peace efforts, American delegations have met repeatedly with the group in Qatar, where the Taliban keep a political delegation.

American officials have expressed optimism, but the Taliban have yet to show willingness to meet with the Afghan government and have promised to continue their attacks.

“The political efforts of the Islamic Emirate for the withdrawal of American invaders should not be misconstrued as meaning that the American invaders will not be targeted militarily or that withdrawing and not withdrawing from Afghanistan are options chosen by American Generals,” the Taliban said in a statement.

Separately on Sunday, the Taliban kidnapped 60 trucks with drivers and their assistants in northern Afghanistan for not paying taxes. The insurgents have increased their efforts in recent years to tax Afghan businesses, and even to collect electricity bills in areas under their control.

The kidnappings took place in the Dara-i-Suf Payin district of Samangan Province, where trucks were transferring coal from the biggest coal mine in the country.

Abdul Yaqin Ahmadi, the governor of Dara-i-Suf Payin, said that tribal elders had negotiated the release of the 60 assistants, but that the drivers and trucks remained in Taliban custody. About 300 trucks transport coal from the area daily.

Last December, the Taliban burned several trucks and abducted their drivers when they refused to pay taxes.

“The Taliban asked these drivers to pay them $100 tax on each truck, which they didn’t,” Mr. Ahmadi said.