Four people were killed and 40 injured after being run over and stabbed in a lightning attack at the gates of British democracy attributed by police to "Islamist-related terrorism".
US Secretary of State Rex Tillerson will skip a NATO meeting in April but travel to Russia the same month, fuelling fears about Washington's commitment to the alliance.
German Chancellor Angela Merkel and Japan's Prime Minister Shinzo Abe issued a staunch joint defence of free trade on Sunday, as the United States pushes towards greater protectionism.
Finance ministers from the world's top nations gather in Germany on Friday as fears grow of a looming trade war over US President Donald Trump's America First policy.
An axe-wielding attacker suffering from mental health problems injured seven people at the main train station in the German city of Dusseldorf late Thursday, police said.
European countries that vote populists into power will experience a fall in jobs, investment and exports as they pull out of the EU, French President Francois Hollande warned on Monday.
German Chancellor Angela Merkel visits Turkey on Thursday for the first time since the failed July coup, seeking to keep a key partnership alive after a series of crises.
Turkey has called on Germany to reject asylum requests by several dozen Turkish soldiers, who reports suggest fear jail over last year's failed coup if they return home.
President Donald Trump vowed Saturday to improve floundering ties with Russia, while also reassuring close US allies he supports NATO.