The US and the Philippines’ defense chiefs slammed Beijing’s recent moves in the South China Sea and pushed to bolster their longstanding alliance, even as Washington seeks to warm ties with China.

US Defense Secretary Lloyd Austin and his Philippine counterpart Gilberto Teodoro Jr. met on the sidelines of Asean Defense Ministers’ Meeting-Plus in Jakarta, according to a joint readout released 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, which is part of Beijing’s sweeping claims over the South China Sea.

The top defense officials 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 conference 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 that 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.