The United States Attorney General Loretta Lynch said she is hopeful that Qatar will co-operate with the ongoing investigation into Fifa corruption.

The FBI is working closely on the investigation with Swiss authorities, whose case is specifically connected to the decision to award the 2018 and 2022 World Cups to Russia and Qatar respectively.

“We will follow the facts and the evidence where it leads us,” Lynch said at a briefing in London. “And regardless of who is handling that investigation, whether it’s us or the Swiss, I think that Qatar’s role in it would hopefully be cooperative.”

Qatar’s al-Udeid air base is the current home for dozens of aircraft involved in the US-led campaign against the Islamic State group in Syria and Iraq.

However, Lynch said military relations with Qatar were not a factor in deciding whether to act on any evidence of corruption in the World Cup vote.

“I think that we make our considerations based on the considerations of the case, based on the evidence, based on the facts, and based on what’s appropriate to handle if we were to discover a problem or corruption or a violation of law that led to a US case,” Lynch said. “We would move on that basis.”

Lynch has led the US investigation into Fifa corruption, which went public in May when 14 people were indicted including Fifa executives. A further 16 men were charged last week over bribes, with two FIFA vice presidents arrested while in Zurich for an executive committee meeting.

In teh wake of the most recent arrests, Lynch expressed disappointment with Fifa and its confederations for rtheir failure to vet appointees.

“It is incumbent upon FIFA to ensure they have the appropriate screening processes, and that they have enough of a view of the specific methodologies that they need to adopt, that regardless of where they come from, there are methodologies and compliance mechanisms that will make the organization stronger,” Lynch said.

“You have to judge people by their actions and see how the next round of leadership handles this responsibility because it is a responsibility both in terms of CONCACAF in particular, CONMEBOL also, but FIFA as a larger organization.

“People have to be vigilant, and the organization has to be prepared to take action itself in terms of holding its leaders accountable.”