US President Barack Obama on Tuesday congratulated Philippines president-elect Rodrigo Duterte on his landslide victory at the polls, hailing the country's "vibrant democracy" -- and emphasizing the importance of protecting human rights.

In the call with Duterte, Obama "highlighted the enduring values that underpin our thriving alliance with the Philippines... including our shared commitments to democracy, human rights, rule of law, and inclusive economic growth," the White House said.

The tough-talking Duterte, who was elected on May 9 on a populist platform, has been accused by rights groups of running vigilante death squads in his home city of Davao. He takes over as president on June 30, succeeding Benigno Aquino.