STOCKHOLM (REUTERS) - US Secretary of State John Kerry said on Tuesday that he expected a proposed Syria peace conference backed by Washington and Moscow to be held in early June, and he denied reports that the Damascus government did not plan to attend.

"If he decides not to come to the table, it would be another one of President (Bashar) Assad's gross miscalculations," Mr Kerry told reporters in Sweden.

"I don't believe that that is the case at this moment. The Russians, Foreign Minister Sergei Lavrov has already given him the names of people who will negotiate."

Syrian Information Minister Omran Zoabi said earlier in the day that Damascus wanted specifics on the proposed conference before it decides whether to be part of it.

Mr Kerry said the exact timing of the meeting was up to the United Nations, but that he expected it would take place in early June, noting that a great deal of work towards the negotiations had already taken place.

"I have talked with almost all of the foreign ministers in the core group who will be meeting next week together in order to lay plans for this negotiation. The members of the opposition have been in touch," he said.

Mr Kerry added that he spoke on Tuesday morning with Syrian opposition General Salim Idriss, and he was committed to the negotiation process.