Officials say no delay in US strategy review after Karzai’s rival pulls out of runoff.
During the ceremony Obama placed a wreath at the Tomb of the Unknowns in the cemetery, which is the final resting place for fallen US soldiers.
Afghan war meeting
The ceremony took place on the same day that Obama was due to hold the eighth meeting of his war cabinet to consider future US military strategy in Afghanistan.
Injured Iraq war veteran gives his thoughts
Obama is considering whether to agree to a request by the senior commander of US and Nato troops in Afghanistan to send up to 40,000 more US troops to the country.
General Stanley McChrystal has warned that the US and Nato risk losing the eight-year campaign against resurgent Taliban and al-Qaeda fighters in Afghanistan unless more soldiers are sent to the country.
But despite calls by US military leaders for more troops to be committed to Afghanistan, US public opinion appears to be against further deployments.
A CNN/Opinion Research Corporation survey released on Wednesday said that 56 per cent of those polled were against deploying more soldiers to Afghanistan, compared to 42 per cent in support of sending more troops.
Forty per cent of those surveyed expressed support for the war, with 58 per cent against it.
Forty-nine per cent of those polled said that Obama is taking too long to decide on US military strategy for the war in Afghanistan, against 50 per cent who said he was not.
The sampling error in the poll was plus or minus three percentage points.