Biden was headed first to a luxurious castle in Germany's Alps for a G7 summit with leaders of Britain, Canada, France, Germany, Italy and Japan. Next week he flies to Madrid for a NATO summit.

Both sessions will take place in the shadow of Russia's Ukraine invasion, but also a global surge in inflation, fears of recession, and the ever-growing challenge of containing China while avoiding open conflict.

Biden has gained widespread praise for restoring US leadership of its European and Asian alliances. The response to Russia in particular has seen strong transatlantic unity, both for arming the Ukrainians and imposing powerful economic sanctions against Moscow.

But Biden, like several European leaders, is facing pressure at home over fallout from the sanctions, which have helped drive up fuel prices, imposing a heavy drag on economies exiting the Covid-19 shutdown.

Biden is also burdened at home by a tense political situation ahead of November midterm elections that could see Republicans take back control of Congress for the next two years.

A ruling by the Supreme Court on Friday to end decades of federal protections for access to abortion has opened a new battlefield, with Biden calling on voters to make it a key issue in November.

He returned to the issue on Saturday before departing for Europe, saying the Supreme Court had made a "shocking decision."

"I know how painful and devastating the decision is for so many Americans," he said.