(Voice Of America) The Philippine government announced Tuesday a new diplomatic protest against China over disputes in the South China Sea, a long-thorny issue that has flared anew as the next Philippine president prepares to take office next month.

The Philippines has filed hundreds of diplomatic protests against Beijing in recent years for what it considers acts of aggression in the disputed waters, despite improved ties between Beijing and Manila under outgoing President Rodrigo Duterte, whose six-year term ends on June 30.

The territorial conflicts are among the key challenges President-elect Ferdinand Marcos Jr. will face when he takes office after his landslide electoral victory on May 9. He has said he will use diplomatic means with China over the issue, the same approach adopted by Duterte, who has been criticized for not taking a more aggressive stance against Beijing’s increasingly assertive actions in the resource-rich and busy waterway.