President Rodrigo Duterte told the United States in February last year he planned to axe the Visiting Forces Agreement (VFA), after Washington cancelled the visa of a close ally who led his internationally condemned war on drugs.

It is the third time Duterte has prolonged the deal, which provides the legal framework for joint military exercises with the United States and is a key component of their decades-long alliance.

"The president conveyed to us his decision to extend the suspension of the abrogation of the Visiting Forces Agreement by another six months while he studies and both sides further address his concerns regarding particular aspects of the agreement," Foreign Secretary Teodoro Locsin said.

A foreign affairs spokeswoman said the department was waiting for details from Duterte's office on the specific areas of concern.

The US embassy in Manila did not respond to a request for comment.

Duterte's decision -- which followed lengthy talks between both sides on the agreement -- comes amid renewed tensions between Manila and Beijing over the South China Sea, where several countries have competing claims.

Duterte has repeatedly threatened to break from long-standing security ties with the United States, the Southeast Asian country's former colonial master, in favour of closer links with China.

The two countries held scaled-down joint drills in April, after last year's war games were cancelled due to Covid-19.