The Associated Press reports that the blasts killed 12 people and set the Shar-e-Naw neighborhood's guest house on fire. Some guests jumped from the guest house upper floors to save themselves.
Six of those killed were U.N. staff, including one American staffer. U.N. spokesperson Adrian Edwards added nine staff members were wounded during the attack.
"This has clearly been a very serious incident for us," Edwards told The AP. "We've not had an incident like this in the past."
Taliban spokesperson Zabiullah Mujahid told The AP his group was responsible for the guest house attack and for rockets that struck the presidential palace and the five-star Serena Hotel elsewhere in town.
"This is our first attack," Mujahid said, referring to a statement the Taliban made three days ago threatening anyone working on the Nov. 7 runoff election between President Hamid Karzai and Abdullah Abdullah.
The rocket that landed in the Serena Hotel's lobby failed to explode but filled the lobby with smoke forcing guests and hotel workers to the basement, according to The AP.