KABUL/KUNDUZ (Agencies) - The United States and Afghanistan took public steps to end a feud on Sunday as the Afghan President toured a city with the US and Nato commander. US Special Envoy for Pakistan and Afghanistan Richard Holbrooke and senior General David Petraeus on Sunday met Afghan President Hamid Karzai in Kabul at a conference reviewing US civilian and military involvement in Afghanistan. The three men sat together at the start of a two-day conference to discuss what Natos International Security Assistance Force (Isaf) said were the shared challenges and opportunities ahead in the war-torn country. The event, involving senior US and Afghan officials, plus key allied partners, comes after Secretary of State Hillary Clinton in January unveiled a long-term, non-military plan to stabilise Afghanistan and Pakistan. It also comes as both Kabul and Washington seek to draw a line under a row sparked by Karzais claims that foreign governments were behind the massive fraud in last years elections that returned him to power. According to The Sunday Times, Afghan President Karzai has cast doubt over Natos planned summer offensive against the Taliban in the southern province of Kandahar, as more than 10,000 American troops pour in for the fight. Karzai threatened to delay or even cancel the operation - one of the biggest of the nine-year war - after being confronted in Kandahar by elders who said it would bring strife, not security, to his home province. Visiting last week to rally support for the offensive, the President was instead overwhelmed by a barrage of complaints about corruption and misrule. As he was heckled at a shura of 1,500 tribal leaders and elders, he appeared to offer them a veto over military action. Are you happy or unhappy for the operation to be carried out? he asked. The elders shouted back: We are not happy. Then until the time you say you are happy, the operation will not happen, Karzai replied. General Stanley McChrystal, the Nato commander, who was sitting behind him, looked distinctly apprehensive. The remarks have compounded US anger and bewilderment with Karzai, who has already accused the United States of rigging last years presidential elections and even threatened to switch sides to join the Taliban. President Karzai and US General Stanley McChrystal met hundreds of elders in Kunduz, the third such trip in recent weeks, in what Nato says is part of its strategy of emphasising the Afghan governments role in military efforts. That strategy has been strained this month by a row in which Karzai drew the wrath of the White House by accusing Western embassies of carrying out election fraud. Karzai had plans to address German troops in northern Kunduz on Sunday, but they were called off at the last minute in a sign of the volatility of a once-peaceful region. Residents and German forces said rockets had fallen near the German base. I call on the Taliban, the Kunduz Taliban: Brothers ... Come and have your say, but not by the gun, Karzai told the gathered elders. You say, 'Foreigners are here. But as long as you fight, they wont leave.