The United States said Thursday that the new Taliban office in Qatar must not be treated as an embassy, as Afghanistan angrily condemned the "theatrical" opening of the new mission.
The Taliban's "Islamic Emirate of Afghanistan" nameplate on the office in Doha has been at the center of a battle between President Hamid Karzai and the United States over US contacts with the Afghan militant group.
Karzai has suspended negotiations with the United States on a security accord in protest at the handling of the opening of the mission.
A US-led international force deposed a Taliban regime in Afghanistan in 2001. But US President Barack Obama and Karzai both called on Qatar to help open the Taliban office to boost negotiations, US deputy ambassador Rosemary DiCarlo told a UN Security Council meeting on Afghanistan.
"The United States supports the opening of the political office of the Afghan Taliban for this purpose," DiCarlo said.
But she added: "We do not recognize the name 'Islamic Emirate of Afghanistan' and are pleased that Qatar has clarified that the name of the office is the Political Office of the Afghan Taliban, and has had the sign with the incorrect name in front of the door taken down.
"We have underscored that the office must not be treated as, or represent itself as, an embassy or other office representing the Afghan Taliban as an emirate, government, or sovereign," the US envoy said.
The United States considers the opening of the Taliban office as "an important first step" toward a political settlement, DiCarlo said.
"While there may be bumps in the road, the fact that the parties have an opportunity to talk and discuss Afghanistan's future is very important," she added.
Afghanistan's UN envoy Zahir Tanin said the Qatar office opened in a "theatrical sequence of events" that contravened the principles set for the Taliban mission.
"Raising the Taliban flag in Doha on Tuesday was just a reminder of a dark and bloody past from which our country still struggles to emerge," Tanin told the Security Council meeting.
Tanin said the Taliban office must only be used for peace talks.
"Any other activity or function undertaken by or with the Taliban office outside the Afghan-led peace talks purposes is unacceptable."
Tanin said that a recent escalation in the "campaign of fear and terror, violence and brutality endanger the prospect of a peace process."
UN envoy to Afghanistan Jan Kubis told the meeting there were "increasingly brutal assaults on high profile targets, high on civilian targets, low on reaching military objectives."
Kubis said 1,061 civilians had been killed and 2,031 injured in attacks between January 1 and June 6, a 24% increase on the same period in 2012. Anti-government groups were responsible for three quarters of the casualties, Kubis added.