US President Barack Obama has told Iran that nuclear talks present "the best opportunity in decades" for the two countries to pursue a better relationship. He warned, however, that there was still much work to do.
In his annual address to mark the Persian new year festival of Nowruz, Obama directly addressed Iran's people and their leaders.
"This year, we have the best opportunity in decades to pursue a different future between our countries," the US president said.
Obama's video message on Thursday followed mixed messages from talks earlier in the day in Switzerland.
US Secretary of State John Kerry and his Iranian counterpart hailed "progress" in negotiations which seek to prohibit Iran from developing a nuclear weapon and to ensure that their nuclear program is used solely for civil purposes.
A European negotiator at the talks, however, said Tehran and the six major powers were still "pretty far from a deal."
Negotiators now have just 11 days to agree to the outlines of a deal which would likely result in Iran scaling back its nuclear program, in return for relief from sanctions which have strangled its oil exports and hammered its economy. Despite numerous rounds of talks around the world, two deadlines last July and November were previously missed.
In his video message on Thursday, Obama said that the "days and weeks ahead will be critical."
"Our negotiations have made progress, but gaps remain," he said, adding that there are "people, in both our countries and beyond, who oppose a diplomatic resolution."
"My message to you - the people of Iran - is that together we have to speak up for the future we seek."
Closer to home, Obama must still convince many of the US Congress' lawmakers of agreeing to such a deal, as well as the easing of sanctions.
Earlier this month, 47 Republican senators warned Tehran that any agreement on their nuclear program could be abolished once Obama leaves office after next year's presidential election.
Relations between the US and Iran thawed for the first time in 35 years in 2013 after Hassan Rouhani took over as the Iranian president - the same year the two countries signed a landmark nuclear deal. The partners, including the P5+1 group, have been pressing for a lasting agreement since then.
ksb/bk (AFP, Reuters, dpa)