The US and the Philippines’ top defense officials slammed Beijing’s recent moves in the South China Sea, as Manila urged China to halt reclamation activities in disputed waters.

US Defense Secretary Lloyd Austin and his Philippine counterpart Gilberto Teodoro Jr. met to discuss ways to bolster their countries’ alliance on the sidelines of Asean Defense Ministers’ Meeting-Plus in Jakarta, according to a joint readout on Wednesday.

The secretaries “denounced the recent harassment” by Chinese vessels toward Philippine coast guard and resupply vessels “conducting lawful resupply operations” around Second Thomas Shoal, where Manila keeps a military outpost through BRP Sierra Madre, a rusting warship it grounded in 1999 in response to Beijing’s occupation of Mischief Reef four years earlier.

Beijing lays sweeping claims over the South China Sea, where it has built artificial islands in recent years with defense infrastructure. It has fiercely opposed Manila’s moves to resupply and repair the outpost and has repeatedly urged Manila to tow away the stranded vessel.

The Philippines’ Department of Foreign Affairs, in a separate statement on Thursday, said its resupply operations are “legitimate” activities within its exclusive economic zone and in line with international law.

China has turned Mischief Reef into a “militarized artificial island” similar to what it did to other reefs in the contested waters, it said. “We call on China to remove all these illegal structures, cease reclamations in the South China Sea, and be accountable for the damages caused by these illegal activities,” the statement said.

Washington and Manila’s defense chiefs also decried China’s “dangerous” operational maneuvers against US aircraft and ships in the South China Sea. China has maintained that its actions in contested waters were lawful.

The readout was released amid Washington’s efforts to improve relations with China, including a Wednesday meeting between US President Joe Biden and Chinese President Xi Jinping on the sidelines of the Asia-Pacific Economic Cooperation summit in San Francisco.

The US and the Philippines’ defense ministers also “committed to explore further opportunities to strengthen bilateral operations and planning,” including military drills next year and an agreement on information-sharing. They also sought “to expand multilateral activities with like-minded partners,” the statement said.

Both officials reaffirmed the Mutual Defense Treaty, which obliges Washington to come to Manila’s defense in case of an armed attack. The treaty “extends to both countries’ armed forces, public vessels, and aircraft — including those of its coast guard — anywhere in the Pacific, to include the South China Sea,” according to the statement.

“Secretary Austin reiterated President Biden’s message that the US defense commitment to the Philippines is ironclad, and emphasized that the United States stands shoulder-to-shoulder with the Philippines in defending its sovereign rights and jurisdiction in its exclusive economic zone,” the readout said.

The US military early this year won access to four more Philippine sites, on top of the initially agreed five bases under the Enhanced Defense Cooperation Agreement.

Following the recent completion of a $24 million runway upgrade at one of the Philippine military bases, the defense chiefs “pledged to further accelerate EDCA implementation,” the readout said.

--With assistance from Andreo Calonzo.

(Updates with statement from Philippine foreign affairs office.)