Rodrigo Duterte has been sworn in as president of the Philippines, after a landslide election victory in May.

The controversial former mayor of Davao City, 71, overthrew the political establishment, promising a "bloody war" on crime and action on corruption.

At his inaugural speech he promised to make sweeping changes to the country's political system.

"I see the erosion of the people's trust in their country's leaders," he said.

"The erosion of faith in our judicial system. The erosion of confidence in the capacity of our public servants to make the people's lives better, safer and healthier."

Nicknamed "The Punisher", Mr Duterte is credited with a dramatic reduction in crime in Davao, but rights groups say it was at the expense of human rights.

He has also promised to end corruption and spread wealth around the country.

Mr Duterte, who has barely left the Davao in the south since his election win, took his oath at a small ceremony at the Malacanang Palace in Manila. Only state media were permitted to cover the event.

Under the constitution, he and his vice-president, Leni Robredo, will both serve a single six-year term.

'A leap into the unknown': Jonah Fisher, BBC News

Rodrigo Duterte revels in his reputation as an outsider and a political maverick .

During 22 years as mayor of Davao, he built a reputation for blunt speaking and for supporting the extrajudicial killing of suspected criminals.

Crime rates fell dramatically but human rights groups estimate that more than 1,000 people were killed with no legal process. Many were executed by shadowy death squads.

Mr Duterte's election campaign was littered with obscenities and populist promises but light on details.

So the country must now wait to see how he delivers on pledges to end corruption, restore the death penalty, and shift to a more federal system of government.

On the international front, despite having bombastically promised to drive a jet-ski to a contested island in the South China Sea, relations between the Philippines and China could be about to improve.

Mr Duterte has indicated that despite differences, and an upcoming ruling from the Permanent Court of Arbitration, he is ready for a more pragmatic, development focused relationship with the Chinese.

After a period of stability under Benigno Aquino, the presidency of Rodrigo Duterte marks a leap into the unknown.

Ms Robredo was sworn in at a separate ceremony in Quezon City, near the capital. Presidents and vice-presidents run separately in the Philippines.

It is the first time the two ceremonies have being held separately, which local media attributed to Mr Duterte's decision to a hold relatively small event.

But there is a notable political and personality gulf between the two leaders.

Ms Robredo, an anti-poverty campaigner, was sworn in by the chairman of the poorest ward of a district in her province, as well as the chairman of the ward in which her new office is located.

She won her new position by a wafer-thin margin against Ferdinand "Bongbong" Marcos, the son of late former dictator Ferdinand Marcos, whose family has staged a remarkable political comeback since being toppled in 1986.