Senior Qatari officials have denied that they are funding Islamic State and other terrorist groups in Syria.
The officials, including Qatar's director of Intelligence, told the BBC that the country had "nothing to hide" over its support for groups fighting the forces of president Bashar al-Assad's regime.
They insisted that Qatar supports only moderate militants, alongside the CIA and other intelligence agencies, and that strict financial controls had been put in place.
The Week
Escape your echo chamber. Get the facts behind the news, plus analysis from multiple perspectives.
SUBSCRIBE & SAVE
Sign up for The Week's Free Newsletters
Join more than 350,000 subscribers and keep yourself informed with a selection of The Week’s most interesting, enlightening and entertaining stories - plus daily puzzles.
Join more than 350,000 subscribers and keep yourself informed with a selection of The Week’s most interesting, enlightening and entertaining stories - plus daily puzzles.
Latest Videos FromThe Week
The comments came ahead of a meeting in London between the UK government and Qatar's ruler Sheikh Tamim bin Hamad al-Thani.
David Cameron is facing "intense pressure" to insist that the Gulf state cuts off its funding to groups with terrorist affiliations, the Daily Telegraph says.
Last week the US government warned that Qatar and Kuwait continue to create conditions that allow funders to send money to terrorist groups. David Cohen, the US official responsible for financial intelligence in relation to terrorism, said the two states were "permissive jurisdictions for terrorist financing".
Stephen Barclay, the Conservative MP for North-East Cambridgeshire, has called for transparency in Britain's relations with Qatar and the Gulf.
"I welcome the fact that the Prime Minister is meeting with the Emir," he told the Telegraph. "As part of these discussions it is essential that the issue of financing Sunni tribes in Syria and Iraq is raised."
He added: "I hope the Prime Minister will then give further details to Parliament. It remains unclear whether money is still flowing from Qatari nationals. There is clear evidence that Qatari nationals have been instrumental in the financing of Sunni terror groups and the Prime Minister should not avoid tackling this issue head on with the Emir."
The BBC's Frank Gardner said the Qatari officials conceded that some Syrian fighters had switched allegiance during the war, and that a number of groups that had initially been regarded as moderate had later gone on to join Islamist militia.
But in his only broadcast last month the Emir insisted: "We don’t fund extremists."
