President Hamid Karzai thanked the United States on the occasion of the fifth anniversary of the September 11 attacks, for its sacrifices in the battle against Taliban and Al-Qaeda in Afghanistan.
The fight against international terrorism must continue with greater resolve, Karzai added in a statement on Saturday.
The United States led the invasion that toppled the extremist Taliban government weeks after 9/11 after the hardliners did not hand over their Al-Qaeda allies blamed for the atrocities.
"The Afghan people join me in expressing my strong solidarity with the People of the United States as you mark the fifth anniversary of the September 11 terrorist attacks," Karzai said in a statement.
Afghanistan, which had long suffered at the hands of terrorism, understood the "tremendous loss", he said.
Karzai said though it was regrettable that it took 9/11 for the world to appreciate the threat of international terrorism when Afghanistan had long called for help against the growing threat.
"For many years, the Afghan people were held hostage in their own country, and subjected to unspeakable atrocities, by foreign terrorists and their Taliban friends," he said.
"The world must continue the fight against the menace of terrorism with greater resolve and dedication," he said.
Karzai said progress in Afghanistan in the past five years would not have been possible without US help.