Iran’s supreme leader on Thursday strongly rejected proposals for direct talks with the United States, effectively quashing suggestions for a breakthrough one-on-one dialogue on the nuclear standoff and other issues.

Iran’s Supreme Leader Ayatollah Khamenei on Thursday rejected proposals for direct talks with the U.S., effectively quashing suggestions for a breakthrough one-on-one dialogue on the nuclear standoff and potentially other issues.

The latest comments mark the Ayatollah’s first reaction since the idea of direct talks received a high-profile boost earlier this week from U.S. Vice-President Joe Biden during a security summit in Munich, attended by Iran’s Foreign Minister.

The statement also could spill over into the negotiations in Kazakhstan later this month between Iran and a six-nation group comprising the permanent U.N. Security Council members plus Germany. Three rounds last year ended in stalemate with Tehran pushing for a roll back of Western sanctions in exchange for any key concessions on its nuclear program.

His apparent references to U.S. sanctions — saying Washington was “holding a gun” to Iran — suggests Iranian envoys will likely stick to demands for relief from the economic pressures before considering any nuclear concessions.

The U.S. this week further tightened sanctions on the Islamic Republic, calling on countries that buy Iranian crude — mostly Asian nations including China and India — to set the money aside and require Iran to use it to buy local products rather than get cash.

Video broadcast

The comments followed another jab at the U.S. — Video broadcast on state TV, purportedly from an advanced CIA spy drone captured in December 2011, after crossing into Iranian airspace from Afghanistan. The video, aired late on Wednesday on Iranian TV, shows an aerial view of an airport and a city, said to be a U.S. drone base and Kandahar, Afghanistan.

U.S. officials said there was no evidence that the latest claims were true.

Despite the tensions, American proposals for direct dialogue with Iran received a cautious welcome on Sunday from Iran’s Foreign Minister Ali Akbar Salehi. But he added caveats — Washington needs to quieten its “threatening rhetoric” for the offer to get real consideration.

All major decisions in Iran must be cleared by the Ayatollah, who has previously opposed direct negotiations with Washington and has shown no inclination of changing his positions.