Xiang Yang Hong 33 Day 18: Chinese Research Vessel's Record-Setting Incursion Continues Near Pag-asa; UNCLOS Note Verbale Silence Reaches Day 13 — Longest in Marcos Administration

China's research vessel Xiang Yang Hong 33, escorted by CCG vessels 5101 and 5309, maintained its unauthorized presence in the Kalayaan Island Group maritime zones near Pag-asa (Thitu) Island for an 18th consecutive day on May 24, 2026 — as Beijing's diplomatic silence on the Philippines' UNCLOS Article 246 note verbale (filed May 11) stretched to 13 consecutive days without a Chinese Foreign Ministry response, cementing its status as the longest unanswered Philippine diplomatic instrument under the Marcos administration. The Xiang Yang Hong 33 departed Guangzhou on April 15 and entered the West Philippine Sea on April 18, spending nearly six weeks conducting what the Philippines describes as 'illegal marine scientific research' across multiple Philippine EEZ features before escalating to a territorial sea incursion at Pag-asa Island (first documented on May 16-17 with Chinese personnel landing on Sandy Cay 2 and Sandy Cay 3). The PCG's formal investigation into the Sandy Cay personnel landing remained ongoing, with PCG Islander aircraft maintaining daily surveillance and radio challenges. AFP WPS Spokesperson Rear Admiral Roy Trinidad's May 24 statement at the Stratbase-KAS forum noted that China's non-response to the note verbale is itself a form of informational and diplomatic pressure — designed to normalize unauthorized Chinese presence in Philippine waters without triggering formal escalation. The Philippines maintained its three-front WPS standoff: (1) Xiang Yang Hong 33 near Pag-asa (Day 18, Sandy Cay investigation ongoing, Day 13 UNCLOS note verbale silence); (2) Scarborough Shoal 'marine nature reserve' — DFA protest of May 11 unanswered; (3) Second Thomas Shoal — BRP Sierra Madre marine garrison facing continued CCG blockade posture. No kinetic engagement or new escalation was confirmed on May 24. China's Global Times and Xinhua framed the vessel's continued operations as legitimate.