Afghan President Hamid Karzai rounds out his Washington visit Thursday, meeting with congressional leaders and touring the burial grounds of many US troops killed in the Afghanistan war. Capping a week spent smoothing over tensions between Kabul and Washington after months spent trading barbs, Karzai and US Secretary of State Hillary Clinton will also speak during a public forum at the US Institute of Peace. Karzai will be accompanied by US Defense Secretary Robert Gates, Chairman of the Joint Chiefs of Staff Admiral Mike Mullen and General Stanley McChrystal, the commander of US and NATO troops in Afghanistan, during his tour of soldiers' graves at Arlington National Cemetery. During the flagship event of the four-day visit, Karzai and US President Barack Obama met at the White House on Wednesday after awkward public spats that strained their alliance and complicated Obama's gamble on a 30,000-strong troop surge designed to forge a US exit from the Afghan battlefield. In the latest violence, officials said Thursday that Afghan and NATO troops killed up to 40 Taliban-linked militants in raids in northern and central Afghanistan overnight. While acknowledging there had been a strain on the relationship, Obama insisted that flared tensions were 'overstated,' as Karzai staged an effusive show of support for US war goals. The pair followed an Oval Office meeting with a press conference that served as both a public bonding session and an effort by Obama to convince wary Americans that the progress of the war was genuine. Karzai put on an assured political performance, at odds with his tirades just weeks ago against foreign interference. 'We are in a campaign against terrorism together, there are days that we are happy. There are days that we are not happy,' said Karzai, wearing his trademark green cloak and sheepskin hat in the ornate East Room. His latest White House appearance came nearly nine years after the September 11 attacks that prompted the United States to launch the war in Afghanistan and Pakistan border areas against the Taliban and Al-Qaeda. Only weeks ago, Obama aides said Karzai's claims that foreigners plotted fraud in Afghan elections were cause for 'genuine' concern, after the US president told Karzai during a visit to Kabul that he must do more to fight corruption. But on Wednesday, Obama smoothed over that row, noting 'progress' by Karzai on anti-corruption efforts, improved governance, and work toward credible parliamentary elections later this year. Karzai pointedly promised to husband billions of dollars of US aid. Obama said he was confident that slow but steady progress would allow him to meet his goal to begin drawing down US troop numbers by July 2011, and was also 'encouraged' by Pakistan's actions against extremists. In one extraordinary moment, Karzai and Obama stood face to face, a few feet apart, as the Afghan leader described his encounter with a war veteran and quadruple amputee at a military hospital on Tuesday. In another overt show of respect for US 'sacrifices,' Karzai was due to visit Thursday Arlington National Cemetery, where many US dead from the war in Afghanistan are buried. Obama also provided an emotionally charged moment, offering Karzai, who has complained repeatedly at Afghan civilian casualties, a glimpse of the burden of being commander-in-chief. 'When there is a civilian casualty, that is not just a political problem for me,' he said. 'I am ultimately accountable... that is something that I have to carry with me... I don't want civilians killed.' Karzai later made the rounds on Capitol Hill and pleaded for patience in his much criticized fight against corruption. He was due to meet with other top lawmakers Thursday. Most senators gave Karzai positive reviews. 'Sounds like things are on a very even keel, very positive, we didn't see any evidence of any lingering problem,' said Senate Armed Services Committee Chairman Carl Levin, a Democrat. Obama also voiced support for Karzai's efforts to woo wavering Taliban members back into Afghan society, but only if they renounced Al-Qaeda and violence. A US military official, speaking on condition of anonymity, said Karzai wanted to negotiate a security agreement that would ensure a US commitment to Kabul beyond July 2011, when the US military drawdown is scheduled to begin. The Afghan leader is also scheduled to visit Fort Campbell, Kentucky, headquarters of the US Army's 101st Airborne Division, on Friday, weeks before the division deploys to Afghanistan. 