MOSCOW -- As the drama over Attorney General Jeff Sessions plays out in Washington, the Kremlin is watching with a mixture of frustration and regret how the uproar is blocking progress on pressing issues on the U.S.-Russian agenda.

Despite the dashed hopes for a quick thaw, however, Moscow is voicing its readiness to wait as long as it takes.

Donald Trump had come into office expressing admiration for Russian President Vladimir Putin and hoping to mend ties with Moscow, which have sunk to the lowest point since the Cold War over the Ukrainian crisis, the war in Syria and other disputes.

But the allegations by U.S. intelligence agencies of Russian meddling in the election to help Trump defeat Hillary Clinton will likely continue to weigh over his administration and prevent it from launching a meaningful dialogue with the Kremlin any time soon.

In a conference call with reporters, Putin's spokesman Dmitry Peskov lamented the lack of co-operation with Washington on Syria beyond the U.S. diplomatic presence at peace talks in Kazakhstan's capital of Astana that Russia and Turkey brokered earlier this year.

"Similarly, there has been no movement forward regarding co-operation in the fight against terrorism, which causes regret," he said.

Trump has repeatedly talked of co-operating with Russia in fighting the Islamic State group in Syria. The administration of former President Barack Obama had ruled out such co-operation because of Moscow's support for its longtime ally, Syrian President Bashar Assad.

"Without waiting for these contacts to start, Russia has been consistently contributing to the fight against terrorism and scoring results," Peskov said, pointing to the Russian military's role in driving the Islamic State group from the historic Syrian town of Palmyra.

Other issues on the tense Russian-U.S. agenda leave even less room for compromise.

On Ukraine, any move by Trump to soften the stance on Russia's annexation of the Crimean Peninsula and its support for a separatist insurgency in eastern Ukraine would anger his congressional foes and put him in an even more precarious position.

If Trump makes any attempt to ease the sanctions imposed on Russia by the Obama administration, he could face strong resistance in Congress.

On the nuclear arms control, Trump's criticism of the 2010 New START treaty would potentially put him on a collision course with Moscow, which has signalled a desire to extend the deal after it expires in 2021.

But for now, the Kremlin is trying to show patience.

Peskov sought to play down Trump's proposal to raise military spending by 9 per cent, saying that's a domestic matter for Washington. "It would hardly concern us until a rise in spending upsets the existing balance of strategic deterrence," he said.

Asked to comment on the developments on Sessions, Peskov cited Trump's description of it as "a total witch hunt" and added: "We have nothing to add to the expansive definition given by President Trump."

Sessions recused himself Thursday from any investigation into communications between Trump aides and Moscow following revelations that as senator, Sessions twice spoke with Ambassador Sergey Kislyak during the 2016 election campaign and failed to say so when pressed by Congress.

Russian Foreign Minister Sergey Lavrov argued that contacts with officials and lawmakers are part of any ambassador's duties. He added that the pressure on Sessions "strongly resembles a witch hunt or the times of McCarthyism, which we thought were long over in the United States as a civilized country."

In the 1950s, Sen. Joseph McCarthy led a hunt for purported communist infiltrators in the U.S. government, often involving unfounded accusations that promoted widespread fear.

Noting Russia won't mimic the U.S., Lavrov added that "if we applied the same principle to Ambassador (John) Tefft's activities in Russia and his contacts, it would have made quite a funny picture."

Deputy Foreign Minister Sergei Ryabkov deplored that Russia has become a tool in the U.S. political struggle.

"Regrettably, influential forces in the U.S. are using relations with Russia as an instrument for achieving certain goals or treating our relations as a collateral damage in their internal fighting," he said in remarks carried by Russian news agencies. "It causes a strong regret, but we aren't making a tragedy out of it."

Ryabkov added that Moscow continues to believe that restoring ties "destroyed by Obama's administration" is a daunting but still achievable goal.

"We will work on it on such a pace, with such intensity and succession of steps that would be comfortable for the American side," he said. "We aren't going to artificially rush any processes. We realize that it will take certain time for the current U.S. administration to make all key appointments and determine its policy priorities, including on the Russian track."