Former presidential challenger Abdullah Abdullah said Hamid Karzai's reelection as Afghan leader was illegal, accusing his rival Wednesday of lacking a mandate to deliver on pledges of unity and reform. Three days after pulling out of a run-off against the incumbent, Abdullah said a subsequent decision by the Independent Election Commission (IEC) to hand Karzai another five years in power had no basis in law and underlined its bias. But the former foreign minister refrained from calling on his supporters to take to the streets. “This (IEC) decision does not have a legal basis,” Abdullah told reporters. “Such a government which lacks legitimacy cannot fight corruption. “A government which comes to power without the people's support cannot fight phenomena of terrorism, unemployment, poverty and hundreds of other problems.” Abdullah delivered a withering verdict on Karzai's rule, saying the Afghan people had hoped for a new chapter in their lives but instead the president had blown a “golden opportunity”. Reiterating earlier calls for his supporters not to resort to violence, he said: “Let there be only one example of law-breaking.” In his first public appearance since his re-election, Karzai vowed Tuesday to “eradicate the stain” of corruption as well as pledging to form a government reflective of the whole of Afghanistan, historically riven by ethnic rivalry. US President Barack Obama tempered his congratulations to Karzai with a call for him to embark on a new drive to crack down on widespread corruption which has helped sour relations between Washington and Kabul. Abdullah said that the current government will not be able to rein in corruption and has wasted the resources and lives of its international allies. Obama is mulling a request from his top commander on the ground for tens of thousands of reinforcements. In a further sign of the international pressure on Karzai, the head of the UN mission in Afghanistan warned the president that the world could desert him if he does not show his commitment to reform in his next Cabinet. “We are really at a turning point,” Kai Eide, the UN special representative to Afghanistan, told US public broadcaster PBS. “I think the debate we've seen over the last few months in the international community will become even more heated, even more difficult, if we do not have an important, positive signal given through the composition of a new government,” he said. “Some Afghans believe that Afghanistan is of such strategic importance that we will stay here whatever happens. It is simply not correct.”