A war of words is continuing between President Hamid Karzai of Afghanistan and Washington.
Last week Mr Karzai accused the West of being behind last year's election fraud.
It was then reported that the Afghan leader had threatened to join the Taliban insurgency if he were pressured further by the West.
The BBC reports a spokesman denied the threat was made, but Washington has said the Afghan leader's comments are troubling.
Last week, the president angered the West by claiming that the "widespread" fraud had been carried out by international agencies, namely elements within the UN and EU.
He later called US Secretary of State Hillary Clinton to allay concerns, saying that Afghans were grateful for the international community's help.
On Tuesday, White House spokesman Robert Gibbs hinted that any future controversial remarks by Mr Karzai could jeopardise a planned invitation to Washington on 12 May.
