As US President Joe Biden began his visit to Europe, where he will meet with his Russian counterpart Vladimir Putin next week, Washington and Moscow have sent tough messages ahead of the much-awaited summit.
Biden arrived in the UK on Wednesday, kicking off his first foreign trip since coming to power in January, reports Xinhua news agency.
Addressing US troops and their families at Royal Air Force Mildenhall base there, Biden said he would deliver a clear message to Putin.
"We're not seeking conflict with Russia," Biden said. "We want a stable and predictable relationship."
"But I've been clear: The US will respond in a robust and meaningful way if the Russian government engages in harmful activities," he warned.
Meanwhile, a Russian court on Wednesday night outlawed Kremlin critic Alexei Navalny's political organisation and labelled it as "extremist".
The ruling prevents those associated with Navalny's Anti-Corruption Foundation and his regional network from seeking public office.
Condemning the court's decision, the US Department of State said in a statement that with this action, "Russia has effectively criminalized one of the country's few remaining independent political movements".
In March, Washington announced sanctions and restrictions against Russian individuals and entities over the alleged poisoning of Navalny.
The US intelligence community assessed that officers of Russia's Federal Security Service used a nerve agent known as Novichok to poison Navalny on August 20, 2020, according to a senior Biden administration official.
Russia has repeatedly denied such accusations, saying the Navalny case is a purely domestic affair and foreign intervention is not allowed.
Biden's first in-person meeting with Putin is scheduled to take place in Geneva, Switzerland on June 16, at the end of his eight-day trip to Europe.
During his trip, Biden will be in the UK till June 13 during which he will attend the G7 Summit and hold bilateral meetings with leaders of member countries.
He will then travel to Brussels, Belgium to participate in the NATO Summit, before meeting Putin.
Ahead of the US-Russia summit, Biden on Monday reaffirmed his support to Kiev in a call with his Ukrainian counterpart Volodymyr Zelensky, in a bid to reassure Ukraine ahead of the summit.
Following the call, Russian Deputy Foreign Minister Sergei Ryabkov said on Tuesday that "irresponsible" US policy will lead to continued tensions in Ukraine.
There may be a chance at productive talks if the US rises above its own interests and focuses on what is best for solving the Ukrainian crisis, Ryabkov said.