A Philippine Coast Guard ship tows a Filipino resupply vessel following damages due to water cannon from a Chinese Coast Guard ship as it was heading towards the disputed Second Thomas Shoal, in the South China Sea, on 10 December 2023; Credit: Philippine Coast Guard/Handout via REUTERS

MANILA (Reuters) - Relations between Manila and Beijing have soured under Philippine President Ferdinand Marcos Jr, with Manila pivoting back towards the United States which supports the Southeast Asian nation in its maritime disputes with China.

Here is a timeline of key events in 2023 that have escalated tensions between the Philippines and China:

3-5 JAN - Marcos holds three-day visit to Beijing where he and Chinese President Xi Jinping agree to set up direct communications between their foreign ministries on the South China Sea.

2 FEB - The Philippines grants the United States greater access to four more military bases under the 2014 Enhanced Defense Cooperation Agreement (EDCA).

13-14 FEB - The Philippines accuses China's coastguard of directing a "military-grade laser" at its troops living aboard an aging warship that Manila deliberately grounded on the disputed Second Thomas Shoal in 1999. Marcos summons China's ambassador.

4 MARCH - The Philippines spots a Chinese navy ship and 42 vessels believed to be manned by Chinese maritime militia personnel in the vicinity of Thitu island, Manila's biggest and most strategically important outpost in the South China Sea.

3 APRIL - The Philippines reveals the locations of the four additional bases that Washington can use under EDCA. Three face north towards Taiwan and one is near the disputed Spratly Islands.

11 APRIL - More than 17,000 Filipino and US soldiers begin their largest ever joint military drills in the Philippines.

22 APRIL - Marcos and his foreign secretary meet China's then-foreign minister Qin Gang in Manila, pledging to work together to resolve maritime differences.

1 MAY - US President Joe Biden welcomes Marcos at the White House, the first visit by a Philippine leader in 10 years. They express "unwavering commitment to freedom of navigation and overflight in the South China Sea".

3 MAY - The United States and the Philippines agree on new guidelines for their 1951 Mutual Defense Treaty, which specifically mention that mutual defence commitments would be invoked in an armed attack on either country "anywhere in the South China Sea".

6 JUNE - The coast guards of the United States, Japan and the Philippines hold trilateral exercises in the South China Sea, the first such manoeuvres.

7 JULY - The Philippine military reports an "alarming" increase in the number of Chinese fishing vessels in disputed waters.

5 AUG - The Philippines accuses China's coast guard of blocking and firing a water cannon against a supply boat transporting food for troops on the Second Thomas Shoal, known in China as Renai Reef and in Manila as Ayungin Shoal.

7 AUG - China's coast guard urges the Philippines to remove a grounded warship from the Second Thomas Shoal.

24-25 SEPT - The Philippines accuses China's coast guard of installing a "floating barrier" near the Scarborough Shoal, and removes the object.

16 OCT - The Philippine military says a Chinese navy ship shadowed and attempted to cut off a Philippine navy vessel conducting a resupply mission near Thitu island.

22-24 OCT - The Philippines accuses Chinese coastguard vessels of intentionally colliding with its vessels routinely supplying forces stationed at the Second Thomas Shoal. No one was harmed.

16 NOV - The Philippines calls on China to remove all "illegal structures" built within its exclusive economic zone (EEZ), cease reclamation in those areas and be accountable for the damage the activities caused.

21 NOV - The militaries of the Philippines and the United States launch joint patrols from waters near Taiwan to the South China Sea.

25 NOV - The Philippines and Australia begin their first joint sea and air patrols in the South China Sea.

3 DEC - The Philippines monitors what it calls the "illegal presence" of more than 135 Chinese maritime militia vessels in the vicinity of Whitsun Reef, which Manila calls the Julian Felipe Reef.

9-10 DEC - The Philippines accuses China of firing water cannons at its boats, including one carrying its military chief, and ramming others, causing serious engine damage. China's coast guard says the Philippine vessel intentionally rammed its ship.

11 DEC - The Philippines calls the actions of Chinese vessels a "serious escalation".

19 DEC - Marcos says a "paradigm shift" is needed in how his country approaches the South China Sea, as diplomatic efforts with Beijing were headed in a "poor direction".

21 DEC - China says bilateral relations are at a crossroads and warns the Philippines against "misjudging" the maritime situation.