Manila: The US and the Philippines are expected to announce a deal on Thursday that will grant US troops access to four more military bases in the Southeast Asian country, as the long-time allies seek to deter Chinese aggression in the region. A senior Philippine official told AFP that the agreement to expand cooperation will be announced during a visit by US Defense Secretary Lloyd Austin, and it comes as the countries seek to repair ties that have been strained in recent years. China's growing assertiveness toward Taiwan and its claims in the disputed South China Sea have given Washington and Manila new impetus to strengthen their partnership. Also Read: This Islamic country to impose Rs 4 lakh crore fine on Pak! Given its proximity to Taiwan and its surrounding waters, cooperation from the Philippines would be critical in the event of a conflict with China, which a four-star US Air Force general has warned could occur as early as 2025. "Agreement has been reached to designate four new additional sites," a Philippine official told AFP on condition of anonymity. The official also stated that discussions for a possible fifth base were ongoing. The two countries have a decades-old security alliance that includes a mutual defence treaty and a 2014 agreement known as EDCA that allows US troops to rotate through five Philippine bases, including those near disputed waters. Also Read: 'Something is wrong,' Elon Musk says as he makes his Twitter account private It also permits the United States military to store defence equipment and supplies on those bases. EDCA stalled during the administration of ex-President Rodrigo Duterte, who favoured China over his country's former colonial master, but the new administration of President Ferdinand Marcos has been eager to speed up its implementation. The United States will have access to at least nine military bases across the archipelago under the EDCA expansion, which will be unveiled on Thursday. The majority of the new bases are expected to be located on the main island of Luzon, the closest Philippine landmass to Taiwan, where the US already has access to two sites. The fourth will reportedly be on the western island of Palawan, facing the contested Spratly Islands in the South China Sea. Austin was scheduled to meet with Marcos at the presidential palace prior to the announcement. According to a senior US defence official, the Philippines is under "day-to-day pressure from (China) in ways that violate international law." The US wants to ensure that "they have the capability to defend their own sovereignty," according to the official. Also Read: Conflict over Abbas's succession may "collapse" Israeli Authority Beijing claims sovereignty over almost the entire South China Sea and has ignored a Hague ruling that its claims lack legal foundation. The Philippines, Vietnam, Malaysia, and Brunei all have competing claims to the sea. China also claims self-ruled, democratic Taiwan as part of its territory, which it intends to reclaim one day, by force if necessary. "Looking at the location of the proposed sites, it appears pretty clear that these sites are in relation to a Taiwan contingency," PSA Philippines Consultancy's Greg Wyatt said.