Taliban military chief Mullah Dadullah told Reuters that Afghanistan had become a "hub of disturbance, killings, looting and drugs" since the Taliban's overthrow in late 2001.
Dadullah, speaking on Friday by satellite phone from an undisclosed location, denounced presidential and legislative elections in October 2004 and 18 September this year as US-staged "dramas".
He said the latest polls for a national assembly and provincial councils had brought in "old murderers and warlords".
"Those who were happy over the fall of the Taliban have now realised the American occupation of their country was just for the sake of American interests," he said.
"It's proven the Americans occupied our country by raising the bogey of terrorism and have no sympathy with Afghans."
Around 50 US troops have been
killed this year
Dadullah called Afghanistan a "drug-manufacturing factory" with government ministers involved in the narcotics trade.
"We will continue our jihad until we drive out foreign troops from our country," he said.
US-led forces overthrew the Taliban in late 2001 after the party refused to had over al-Qaida leader Osama bin Laden, mastermind of the 11 Septemberattacks.
Four years on, bin Laden and Taliban leader Mullah Mohammad Omar remain at large and the Taliban continue to wage a guerrilla war against President Hamid Karzai's Western-backed government and around 30,000 foreign troops.
More than 1000 people - mostly rebels, but including more than 50 US troops, have died this year, the bloodiest since 2001.
Today there are conflicting views among analysts about US-led efforts to build a stable democracy in Afghanistan.
Success or failure?
This week, James Dobbins, a former US envoy to Afghanistan, hailed the Bonn Agreement aimed at putting in place a moderate, reform-minded government as a "remarkable success".
Taliban say the polls brought in
'murderers and warlords'
But speaking at Washington's George Washington University on Wednesday he said security had not yet been established throughout the country and economic development needed boosting with the continued help of international backers.
Afghanistan expert Ahmed Rashid gave a gloomier assessment, saying the hard work for Karzai was still to come with little by way of reform achieved since 2001 and international backers appearing to waver, even as the Taliban step up their
Writing for YaleGlobal Online, Rashid said initial indications were that warlords and their supporters would dominate the new parliament and would seek to block reform and to force Karzai to drop progressive voices from his cabinet.
"Instead of spurring on development goals and reconstruction, the parliament will likely become a major hindrance for both," he wrote, adding that the lower turnout in the latest elections compared with last year was a sign of popular disillusionment.