WASHINGTON - Cracks in the relationship between Washington and President Hamid Karzai following last weeks elections suggest the US will face an even tougher battle to implement its new strategy for Afghanistan, according to media reports on Saturday. Some reports in the American press said US envoys and lawmakers have bluntly warned Karzai that American patience is running out, citing concerns about allegations of fraud and corruption and attempts to prejudge the outcome of last weeks election. Karzai met twice with US President Barack Obamas envoy to Afghanistan, Richard Holbrooke, after the August 20 presidential election, including a private lunch in Kabul that turned tense when the US envoy raised the possibility of a run-off, us official were cited as saying. US tensions with Karzai, in meetings with Holbrooke and a visiting delegation of US senators, reflected both election-time stress and growing discord in American relations with the man who has been leading Afghanistan since the Taliban was overthrown in 2001. Allegations that Karzai compromised himself in his efforts to be re-elected could hinder international and U.S. efforts to get Afghanistan on track, The New York Times said in a dispatch. Karzai struck deals with warlords and drug dealers in the weeks leading up to the election and since has portrayed himself as the only candidate willing to stand up to the Obama administration, it said. Afghanistans Electoral Complaints Commission said Friday that it had received more than 2,000 complaints of fraud or abuse in last weeks election. Karzais biggest rival, Abdullah Abdullah, showed reporters video of a local election chief in one polling station stuffing ballot boxes himself, the Times said. The vote count has progressed very slowly in Afghanistan as of Friday, preliminary results with 17 percent of the vote in gave Mr. Karzai 44 percent and Abdullah 35 percent. If no candidate wins 50 percent of the vote, a runoff must be held between the top two candidates. Privately, Karzai already has predicted victory despite the more than 2,000 complaints of fraud or abuse filed with Afghanistan's Electoral Complaints Commission, the Times reported. For President Barack Obama, who is on vacation here in Marthas Vineyard, and his administration, it is the worst of all possible outcomes, the Times said. Administration officials have made no secret of their growing disenchantment with Karzai. "But Mr. Karzai, in a feat of political shrewdness that has surprised some in the Obama administration, has managed to turn that disenchantment to an advantage, portraying himself at home as the only political candidate willing to stand up to the dictates of the United States", the newspaper said, citing Western officials. Endemic government corruption and his close ties with former militia leaders have eroded Karzais support, both with the Afghan people and with Washington policymakers. The Obama administration was particularly disturbed by Karzais last-minute alliance with Uzbek General Abdul Rashid Dostum, officials said. He [Karzai] has hurt himself in the eyes of a lot of people, a Western observer close to US deliberations explained of Dostums role in President Karzais campaign. US officials say Dostom, who fought for Afghanistans Soviet-backed Communist government and later switched sides repeatedly during years of factional civil war, may be responsible for war crimes. Karzai justified the move to Washington, telling officials he believed Dostum, who enjoys the overwhelming backing of ethnic Uzbeks in the north of Afghanistan, delivered key votes that could put him over the top. Karzai would need more than 50 percent of the vote to avoid a run-off, but partial tallies so far show a close race with his leading challenger, Abdullah Abdullah. A new Washington Post-ABC News poll showed most Americans believe the war in Afghanistan is not worth fighting and only a quarter say more troops should be sent there.