US Secretary of State Antony Blinken has assured the Philippines, a key Washington ally, of US support in the midst of heightened tensions with China.

He reiterated America's "ironclad" security commitments to the South-east Asian country during a visit to Manila on Tuesday, reports BBC. 

"These waterways are critical to the Philippines, to its security, to its economy," Blinken said.

"They're also critical to the interests of the region, the United States and the world," he added, speaking at a joint press conference with Philippine Foreign Secretary Enrique Manalo.

"That's why we stand with the Philippines and stand by our ironclad defence commitments, including under the mutual defence treaty."

Manila and Washington are "committed to elevating" their alliance further, Manalo said.

"I think our relationship with the United States has never been higher, greater," he said when asked by the BBC about the value of Washington's commitments ahead of this year's election in the US.

Blinken will also discuss trade with Filipino officials, a senior State Department official has said.

The visit is also likely to be seen as bolstering American support for Philippine president Ferdinand Marcos Jr, who has tilted towards Washington unlike his predecessor Rodrigo Duterte, who pushed ties with Beijing.

Bd-pratidin English/Lutful Hoquw