It's unclear whether Kerry has formed his own opinion. Asked during his confirmation hearing last month about new options for Syria, he said he needed to first see the administration's contingency plans.
"What I do know is that there are a lot of weapons there," he said. "There are people in the Gulf, and you know who they are, who are not hesitating to provide weapons. And that's one of the reasons, together with the fact that al-Nusra has been introduced to the equation that the movement on the ground is faster than the movement in the politics."
Looking ahead to nuclear talks later this month between Iran and senior officials from the five permanent members of the U.N. Security Council and Germany, Kerry warned Iran to come prepared to talk seriously about concerns over its nuclear program.
If Iran does what it needs to do to prove its nuclear intentions are peaceful, Kerry said the international community is prepared to respond positively. If not, he said Iran will only face increased international isolation.
Kerry reminded the Iranian leadership that Obama has taken no options off the table, including military force, to prevent Iran from obtaining a nuclear weapon.
"Iran has a choice," he said. "They have to prove to the world that it is peaceful and we are prepared to sit responsibly and negotiate how they can do that and how we can all be satisfied."
Associated Press writer Matthew Lee contributed to this report.
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