Russian Foreign Minister Sergei Lavrov delivers a speech during a session of the State Duma. REUTERS/Sergei Karpukhin

The United States declined to host a high-ranking Russian delegation on Syria and also refused to send its own mission to Moscow, Russia’s foreign minister said on Wednesday.

On Tuesday, Russian President Vladimir Putin accused Washington of refusing to cooperate and share intelligence on Syria and said he was willing to send a high-profile delegation led by Prime Minister Dmitry Medvedev to the United States.

“Literally today, we got an official reply,” Russian Foreign Minister Sergei Lavrov said, speaking in parliament.

“We have been told that they can’t send a delegation to Moscow and they can’t host a delegation in Washington either,” he said.

Putin, speaking at an investment forum on Tuesday, said Russia’s delegation could include military officials at the level of deputy chief of the General Staff as well as members of security services.

“It is time to take this work to a serious, substantial level, if we really want to work effectively,” Putin said.

But Putin also expressed some of his strongest criticism yet of Washington’s handling of the Syrian crisis, saying the United States did not seem to know what its goals were in the Middle Eastern country.

“I believe some of our partners simply have mush for brains,” he said.

At the same time Russia and the United States — which are both bombing Islamic State targets in Syria — have nearly reached an agreement on staying out of each other’s way in the sky, Lavrov said.

“It should become operational literally any day now,” the country’s top diplomat told the Russian parliament’s lower house, the State Duma, adding he was hoping that all the formalities would be agreed on Wednesday.

US Defence Secretary Ash Carter for his part said earlier that Washington and Moscow would have another round of “de-confliction” talks.

“Those discussions are progressing. Nothing has been finalised,” Carter said.

Late last month Moscow launched a bombing campaign in Syria, saying it needed to target Islamic State jihadists before they cross into Russia, which has a large Muslim population.

But Washington and its allies slammed Russia’s intervention in the multi-front conflict, saying Moscow was also targeting Western-backed moderate rebels and seeking to prop up the regime of Bashar al-Assad.

Putin announced the launch of strikes after meeting US President Barack Obama on the sidelines of the UN General Assembly last month.

Lavrov said Putin had told Obama of his plans to intervene militarily in Syria during their meeting. Putin made the proposal to send the high-ranking delegation to Washington at the UN General Assembly too, he said.