DOHA, Qatar -- Qatar's top diplomat on Tuesday promised that his country would host a successful World Cup in 2022 and suggested that criticism of its successful bid was partly based on racism.

The bid is under renewed scrutiny following the launch of American and Swiss investigations into corruption at football's world governing body, FIFA.

Foreign Minister Khalid al-Attiyah reiterated Qatar's stance that it has and will continue to co-operate with investigators. He said he was confident the event would go ahead and will be "the best World Cup ever."

He also hit back at international criticism of Qatar, saying "some parties cannot digest that a small, Arabic state ... is hosting such an event."

Al-Attiyah acknowledged that more needs to be done to improve conditions for migrant labourers at World Cup sites.