Trump tells Russia's top diplomat to rein in Syria's Assad

President Donald Trump laid on a White House welcome for Moscow's top diplomat to seek help to end the war in Syria, as Washington reeled at the dismissal of FBI chief James Comey, who had been probing Russia's alleged interference in the US election.

Secretary of State Rex Tillerson has admitted that US-Russian relations are at their lowest ebb since the Cold War, and that there is almost no trust left. But both Trump and a beaming Russian Foreign Minister Sergei Lavrov Lavrov appeared to strike a more conciliatory tone at Wednesday's meeting.

Diplomats are working to thaw ties by resolving small issues, which officials told AFP includes day-to-day battles such as US complaints that its officials posted to Russia are subjected to low-level covert harassment.

But Trump remains hopeful that Putin can be convinced to help end the Syrian civil war by reining in Russia's ally President Bashar al-Assad and his other key foreign backer, Iran.

Trump "emphasised his desire to build a better relationship between the United States and Russia," the White House said.

'Very, very good' talks

Trump described his talks with Lavrov as "very, very good". When asked whether Comey's dismissal had affected his meeting, Trump said, "not at all". He and Lavrov said they discussed the civil war in Syria.

"We want to see the killing, the horrible killing, stopped in Syria as soon as possible and everyone is working toward that end," Trump told reporters.

Lavrov is the highest-ranking Russian official to visit Washington since Trump came to power in January, and earned a rare invitation to the Oval Office for a head-to-head.

This followed a similar visit last month by Tillerson to Moscow, where he was received at the Kremlin by Putin.

We want to see the killing, the horrible killing, stopped in Syria as soon as possible

- US President Donald Trump

Before visiting the White House, Lavrov and Tillerson huddled to discuss the crises in Syria and Ukraine - talks qualified by the veteran Russian diplomat as "constructive".

"As active players in the diplomatic process regarding Syria, we are going to pursue these contacts together and with other key countries, especially those in the region," Lavrov said.

Lavrov, who last set foot in Washington in August 2013, dismissed all claims of election meddling as "fabrications" - echoing Trump's claim that they amount to "fake news".

"President Trump clearly confirmed his interest in building mutually beneficial, business-like pragmatic relations," he told journalists.

In Moscow, Putin met with his security council to discuss US-Russian relations in the context of Lavrov's meeting with Trump, Kremlin spokesman Dmitry Peskov said.

Resetting relations

Relations between the two former Cold War foes soured under former president Barack Obama over Russia's 2014 annexation of Crimea and its unyielding support for Assad.

Since March 2011, the Syrian conflict has caused more than 320,000 deaths and forced millions to flee the war-ravaged country.

Neither Washington, which backs the opposition, nor Moscow, a longtime ally of the Syrian government, has managed to find a solution to the conflict.

Since the end of Obama's presidency in January, the United States has gradually withdrawn from the diplomatic process, leaving Russia to take the lead.

The US was not part of a deal by Damascus backers Russia and Iran, and rebel supporter Turkey, signed Thursday in the Kazakh capital Astana on establishing safe zones in Syria.

‘De-escalation zones'

The agreement calls for the creation of four "de-escalation zones" to shore up a ceasefire, ban flights and allow for humanitarian aid deliveries.

Washington gave the deal a cautious welcome, rejecting Tehran's proposed role as a guarantor even as it expressed hope the agreement could set the stage for a later settlement.

"We will look at the proposal, see if it can work," Pentagon chief Jim Mattis said on Monday.

Several ceasefires have been agreed on since Syria's conflict broke out, but they have failed to stem the fighting.