Abdullah, who pulled out of a run-off poll scheduled after more than a million votes cast in the August 20 election were deemed fraudulent, said Karzai lacked legitimacy after being re-appointed by electoral commissioners.

“This decision does not have a legal basis,” he told reporters in his first public appearance since Karzai was declared president for another five years.

Abdullah took swipe at his rival’s pledge to eradicate corruption and build national unity following heavy US pressure to clean up widespread graft.

“Such a government which lacks legitimacy cannot fight corruption,” he said.

“A government which comes to power without the people’s support cannot fight phenomena of terrorism threats, unemployment, poverty and hundreds of other problems.”

Karzai was declared president for a second term after the Independent Election Commission (IEC), whose chief he appointed, cancelled a run-off ballot following Abdullah’s withdrawal on Sunday.

Under pressure from US President Barack Obama to wipe out corruption after a turbulent election process steeped in fraud, Karzai used his first appearance since electoral authorities declared him president to pledge a cleaner rule. Related article: UN warns Karzai

Abdullah reiterated long-standing accusations against the IEC of “incompetence and bias,” adding: “This is the very same commission which has announced the appointment of the president.”

“This decision does not have any legal basis and a government which takes power based on such a commission’s decision cannot have legitimacy,” he said.