STOCKHOLM — President Bashar al-Assad’s government has given Russia the names of officials who would attend international talks intended to end the war in Syria, Secretary of State John Kerry said Tuesday, even as representatives of both sides in Syria publicly expressed skepticism about the prospect of a political settlement.

Mr. Kerry, who arrived in Sweden to attend a meeting of Arctic nations, also spoke on Tuesday morning with the leader of the Free Syrian Army, Gen. Salim Idris, to discuss the proposal for a peace conference that Mr. Kerry unveiled last week after meeting in Moscow with President Vladimir V. Putin. Neither side has publicly committed to attend the talks, nor has a date been set, though Mr. Kerry and Russia’s foreign minister, Sergey V. Lavrov, said they hoped to convene the conference within a month under the auspices of the United Nations.

“I keep hearing some people suggest somehow that the process is moving away, not closer,” Mr. Kerry said during remarks with Sweden’s prime minister, Fredrik Reinfeldt. “I just don’t agree with that. Enormous plans are being laid.”

Mr. Kerry did not disclose the names of the Syrian officials that were passed to the Russians.

“If President Assad decides to miscalculate again about that, as he has miscalculated about his own country’s future over the course of the last years, it is clear the opposition will be receiving additional support,” he said, suggesting that the flow of arms to the rebels would increase. “There will be additional efforts made, and unfortunately the violence will not end.”