Britain’s foreign secretary is calling for traditional Western allies to join in a united front against Russia’s “aggressive and malign behavior,” expressing confidence that the United States under President Donald Trump will lead the way.

British Foreign Secretary Jeremy Hunt told an audience in Washington it is essential for the U.S., Britain and the European Union to stand firm against Russian President Vladimir Putin’s increasingly dangerous attacks on long-standing international norms.

“Those who don’t share our values, need to know that there will always be a serious price to pay if red lines are crossed by the territorial incursions, the use of banned weapons, or increasingly cyberattacks,” Hunt said Tuesday prior to talks with U.S. Vice President Mike Pence and Secretary of State Mike Pompeo.

“He [Putin] is testing us,” Hunt added. “He is just wanting to see just how robust and how united the West is.”

Actions against Russia

Hunt said there are several reasons for optimism, praising the United States for its strong stance on Russia following the March poisoning of a former Russian agent and his daughter in the British town of Salisbury.

The U.S. expelled 60 Russian diplomats and imposed sanctions, pointing to the use of a Soviet-era nerve toxin known as Novichok.

U.S. and British officials have also accused Russia of seeking to interfere with their elections.

At the same time, U.S. President Donald Trump has repeatedly cast doubt on assertions that Russia sought to meddle in the U.S. election, taking to social media to dismiss an investigation into Russia’s actions as a “rigged witch hunt.”

And in an interview Monday with the Reuters news agency, Trump said he would consider lifting sanctions against Russia in exchange for cooperation in Syria or Ukraine.