The two-day sail includes three Indian vessels and started Sunday, a day ahead of Philippine President Ferdinand Marcos' scheduled trip to New Delhi for talks with Indian Prime Minister Narendra Modi.

The Philippines has heightened defence cooperation with a range of allies over the past year after a series of clashes in the contested waterway.

Beijing claims nearly the entirety of the South China Sea despite an international ruling that its assertion has no legal basis.

India's naval vessels arrived in Manila for a port visit late last week.

The patrol "started yesterday afternoon, then it's ongoing up to this moment... the activity at the moment is replenishment at sea," Lieutenant Colonel John Paul Salgado told AFP.

While in India, Marcos is expected to sign pacts in such fields as law, culture and technology, according to Foreign Affairs Assistant Secretary Evangeline Ong Jimenez-Ducrocq, but all eyes will be on any potential defence agreements.

The Philippines has previously purchased BrahMos supersonic cruise missiles from India, a weapon which has a top speed of 3,450 kilometres (2,140 miles) per hour.

India, which has engaged in border clashes with China in the Himalayas, is a member of the so-called Quad, a group that includes fellow democracies the United States, Japan and Australia.

Beijing has repeatedly alleged that the four-way partnership, first conceived by late Japanese prime minister Shinzo Abe, was created as a way of containing China.