The US ambassador to Afghanistan has warned President Obama against sending more troops to prop up what he called the corrupt leadership in Kabul. Karl Eikenberry is a former American military commander in Afghanistan. He has expressed deep reservations about what he termed President Hamid Karzai’s “erratic behaviour” and the rampant corruption in his government.Obama is considering sending up to 40,000 more troops to fight the Taliban. But waning public support for the war has delayed any decision. Karzai was re-elected as president last week after a vote seen by many as deeply fraudulent. Claims of ballot-rigging forced him into a run-off which was then cancelled when his only rival pulled out.