But Foreign Ministry spokesman Janan Mosazai said the Afghan government remains willing to send a peace delegation to Doha to negotiate with the Taliban once it has its explanation, as well as assurances that the office will be nothing more than a place for talks.
"The Afghan government remains fully committed to pursue a process of peace negotiations with the armed opposition, including the Taliban, but within the confines of the conditions and the principles and the assurances that we have established," Mosazai told reporters in Kabul.
The Taliban's office opened Tuesday in a ceremony broadcast on live television, accompanied by a simultaneous announcement that US officials would begin formal talks with Taliban representatives, which eventually would be joined by the Afghan government.
That raised hopes that the long-stalled peace process could finally begin.
But the Taliban's use of its old flag and a sign bearing the name of the Islamic Emirate of Afghanistan, which the movement used during its five-year rule that ended in 2001 with the US-led invasion, provoked outrage across party lines in Afghanistan.
The Taliban has since complied after the Qatar government intervened. Both the US and the Qataris said the Taliban had agreed on the pre-approved name but violated the pact at the ribbon cutting ceremony.
