Image copyright AFP Image caption The agreement allows US troops to take part in joint exercises in the Philippines

The Philippines has officially told the US that it is scrapping a security pact that allows US forces to train and take part in joint exercises there.

Philippines' President Rodrigo Duterte has long threatened to move away from his country's long-term ally and pivot towards China.

His foreign secretary tweeted that official notice had been given on the Visiting Forces Agreement.

That notice starts a 180-day period until the agreement lapses.

The US said the move would have significant implications for the two country's relations.

Last month President Rodrigo Duterte warned that he would cancel the agreement after the US revoked a travel visa issued to a political ally.

Ronald dela Rosa has been linked to the campaign in which thousands of suspected drug traffickers have been killed.

The volatile president has made various statements on the future role of the US military in his country since he came to power in 2016.