Imran Khan, the Pakistani cricketer-turned-politician, has led thousands of his supporters on a march from the capital, Islamabad, to the country's restive tribal belt to protest against US drone strikes.
The march drew large crowds along the 44km route with thousands showering Khan's convoy with rose petals.
Several American anti-war activists joined the march.
US drone strikes on suspected terror targets have been deeply unpopular with the Pakistani population as many civilians have been killed in the raids.
According to one estimate, the US carried out 300 drone strikes in Pakistan during the last eight years, killing more than 2,500 people in North Waziristan alone.