United States’ Secretary of State Rex Tillerson on Wednesday held a meeting with Russia’s Foreign Minister Sergei Lavrov during which both the top diplomats acknowledged the worsening relations between the two countries in the last couple of months amid the Syrian crisis. Later, Russian President Vladimir Putin met Tillerson.

Tillerson’s visit to Moscow comes at a crucial time when the US has launched a missile strike against Russia-backed Bashar al-Assad regime after an alleged chemical attack in Syria. Both Tillerson and Lavrov discussed the fallouts of the attack for about three hours. Tillerson’s visit was marked by awkwardness, reported Reuters. While Lavrov reiterated Russia’s support for the Syrian President Assad and denied that the government carried out the purported chemical attack, Tillerson maintained that Assad must eventually give up his power in Syria.

However, Lavrov said that a working group would be set up to examine the worsening ties between US and Moscow and added that Putin has also agreed to reactivate the US-Russian air safety agreement over Syria. Tillerson, who is a former oil executive, is considered the best envoy to improve ties with Russia, reported AFP. He has earlier worked closely with the Kremlin and negotiated deals for energy major ExxonMobil. “The world’s two foremost nuclear powers cannot have this kind of relationship,” said Tillerson.

Before meeting Tillerson, Putin had complained of deteriorating ties with Trump’s administration. “You can say that the level of trust on a working level, especially on the military side, has not improved but most likely worsened,” Putin said in an television interview. He questioned the deadly chemical attack that killed dozens in the country’s rebel-held Idlib province. “Where is the proof that Syrian troops used chemical weapons? There isn’t any. But there was a violation of international law. That is an obvious fact,” said Putin in an obvious reference to US missile strikes.

The Syrian Army has said that the strike had killed six personnel and caused “big material losses. Hours before launching the missile strike, Trump had said that the poison gas attack had “crossed a lot of lines” for him. Trump also made a similar statement in Washington. He said that the relationship with Moscow “may be at an all-time low.”