Qatar held separate bilateral meetings with the United States and Iran this week that touched on Iran's nuclear program and U.S. concerns about Iranian drone transfers to Russia, two sources familiar with the matter said on Wednesday.

The sources said the meetings have not involved the kind of shuttle diplomacy Qatar conducted in Doha this year in which Qatari diplomats went back and forth between the two sides, ultimately leading to Monday's U.S.-Iran prisoner exchange.

Qatar, a wealthy Gulf Arab state with diplomatic ambitions, is pressing both sides to engage in more talks and reach "understandings," sources said earlier.