KIRUNA, Sweden – U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov met late on Tuesday for a discussion focused on the war in Syria and plans for an international peace conference, a senior State Department official said.

Kerry updated his Russian counterpart on his discussions with the Syrian rebels and officials from countries involved in the talks and his plans to participate in a meeting in Jordan next week ahead of the international conference, a senior State Department official said.

Russia has been a staunch ally of Syrian President Bashar al-Assad, blocking new sanctions against Syria at the United Nations and supplying the government with arms.

Kerry had said earlier on Tuesday he expected the proposed peace conference to be held in early June, and denied reports that the Damascus government did not plan to attend.

Syrian Information Minister Omran Zoabi said earlier in the day that Assad's government, fighting an insurgency that threatens to draw in Syria's neighbours, wanted specifics on such a conference before it decides whether to be part of it.

Kerry is visiting Sweden for a meeting of the Arctic Council, a grouping of eight nations with Arctic territory.

Kerry had said earlier the exact timing of the Syria peace negotiations was up to the United Nations, but that he expected it would take place in early June, noting that a great deal of work 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.

At his earlier news conference, Kerry reiterated the Obama administration's desire for a peaceful resolution to the two-year-long Syrian civil war, which has killed at least 82,000 people by an opposition estimate and could destabilise the wider Middle East.

Assad's departure has been a demand of the opposition since the revolt started and previous peace initiatives have foundered over the failure to settle on the president's future role.