Afghan President Hamid Karzai on Wednesday ordered an immediate and urgent upgrade of security for international organisations after Taliban suicide gunmen stormed a guesthouse killing six UN staff.
A UN spokesman confirmed six expatriate UN staff was killed and another nine wounded. The guesthouse had UN approval.
"The president instructed security agencies to reinforce security at foreign installations for better protection against such incidents," a statement from the presidential palace said.
The Taliban claimed responsibility and vowed to continue attacks ahead of a presidential election run-off scheduled for November 7.
Kabul's luxury Serena Hotel also came under attack, with two rockets landing in its gardens as the guesthouse was still under seige, police said.
Karzai was forced into a run-off against Abdullah when he fell fractionally short of the 50 per cent threshold in the first round, after around a third of his initial tally of votes were disqualified through fraud.