The Senate is "constantly monitoring" developments in the West Philippine Sea, particularly the country's resupply mission to its military outpost on BRP Sierra Madre, Senate President Juan Miguel "Migz" Zubiri said Friday.

In a Viber message, Zubiri confirmed that the Senate is closely coordinating the situation in the West Philippine Sea with the Philippine Navy and the Philippine Coast Guard.

"Yes, absolutely. We are constantly monitoring [it]," he told reporters when asked for more information about the successful resupply mission to the Ayungin Shoal.

Earlier, Armed Forces of the Philippines chief General Romeo Brawner Jr. said that the recent resupply mission of the Philippines to Ayungin Shoal was successful.

In a video provided by Zubiri, Chinese Coast Guard ships and militia vessels were seen attempting to block the country's resupply mission.

The Senate chief slammed Beijing's efforts to obstruct Manila's resupply mission in Ayungin Shoal, where the BRP Sierra Madre had been run aground.

"This is a humanitarian resupply mission. Only barbarians at the gate will delight at seeing soldiers on a peaceful mission denied of food," he said.

"As long as the law and truth are on our side, illegal barriers to what is ours will continue to be pierced, by the sharp tip of world opinion that upholds our cause as just," he added.

This is not the first time CCG attempted to block and harass resupply missions by the Philippines. Last month, CCG used a water cannon and carried out dangerous maneuvers against Philippine vessels led by the Philippine Coast Guard while en route for a resupply mission to the BRP Sierra Madre.

In that incident, only one of the two Philippine ships was able to provide water, food, and other supplies to the military personnel in the dilapidated warship.

Despite these recent successes, Zubiri said that the Philippines must "remain absolutely cautious and vigilant."