image sourceReutersimage captionRodrigo Duterte became president of the Philippines in 2016

Philippine President Rodrigo Duterte has accepted his party's nomination to run as vice-president in the next election.

The constitution bars Mr Duterte from a second term and rivals have accused him of seeking to cling onto power.

But Mr Duterte claimed that he is driven by love of his country.

There has been speculation he would seek a politically weak running mate in order to rule from the number two role, the BBC's Celia Hatton reports.

Mr Duterte has also mused publicly that as vice-president, he would be immune from prosecution by the International Criminal Court for ordering what he's called "a war on drugs" that has killed thousands. But it is unclear whether he would retain legal immunity.

Mr Duterte had urged senator and close ally Christopher "Bong" Go to succeed him, but Mr Go declined the party's presidential nomination on Wednesday, saying that his "heart and mind are focused on serving people".

While his party says it wants Mr Go to reconsider his decision, his rejection of the nomination has led to suggestions that President Duterte's daughter could join him on the ticket.

Sara Duterte Carpio has given mixed messages about running, despite leading every opinion poll conducted this year.

Mr Duterte won the presidency in 2016 on a platform of crushing crime and fixing the country's drugs crisis but critics say that he has encouraged police to engage in extrajudicial killings of suspects.

In June, the prosecutor of the International Criminal Court applied to open a full investigation into drug war killings in the Philippines, saying crimes against humanity could have been committed.

An Amnesty International report found that more than 7,000 people were killed by police or unknown armed attackers in the first six months of Duterte's presidency.