The United Nations and the European Union lead the chorus of condemnation on Wednesday after Taliban suicide attackers burst into a UN residence in Afghanistan and shot at least eight people dead.
UN Secretary General Ban Ki-moon described the dawn raid as "despicable and brutal."
"I condemn in the strongest possible terms the despicable and brutal killing, for which the Taliban has claimed responsibility in an apparent effort to disrupt the second round of the presidential elections," he said.
Current EU presidency holder Sweden said the bloc was "shocked and appalled by this heinous act of terrorism."
US Secretary of State Hillary Clinton called the murders a "cowardly attack" and said the US was committed to ensuring Afghanistan can hold next week's run-off of its disputed election.
"I strongly condemn the cowardly attack today in Afghanistan," Clinton said during a visit in neighbouring Pakistan.
"We remain firm in our commitment to Afghanistan and the Afghan people and to working with the Afghans to conclude their Presidential election process," she added.
In Brussels, NATO Secretary General Anders Fogh Rasmussen said that "the Taliban has demonstrated once again that it is truly an enemy of the Afghan people" with these killings.
"The victims of these terrorist attacks were devoted to helping the Afghan people build better lives," Rasmussen said.
French Foreign Minister Bernard Kouchner, whose country has more than 2,500 troops in Afghanistan, vowed that Taliban violence would not prevent the presidential run-off from going ahead.
"The Taliban's goal is clear: kill innocent people and terrorise public opinion to prevent Afghanistan getting back on its feet and to disrupt the electoral process that Afghans have bravely put in place," he said.
Canada's Foreign Affairs Minister Lawrence Cannon said the murders were "cowardly" but urged the Afghan people not to be deterred from voting by the violence.
"We encourage all Afghans to exercise their hard-won right to determine the future of their country by participating in the second round of voting," he said.
Taliban suicide gunmen stormed a UN hostel in Kabul early Wednesday morning, killing at least five foreign staff in an assault the Islamist militia said marked the start of a bloody countdown to new Afghan elections on November 7.
Two security personnel were also killed, and a charred, unidentified body was found in one of the rooms.
An Afghan defence ministry official said the raid was the work of Pakistani Taliban dressed as police. Witnesses said the militants sprayed the guesthouse with gunfire and detonated grenades before blowing themselves up.
The United Nations is helping to organise the run-off round next week in Afghanistan's presidential election, following a first round marred by reports of large-scale fraud.