MANILA (UPDATE) — Candidates from the opposition slate Otso Diretso failed on Monday to visit Scarborough Shoal as they brought their campaign to the coastal town of Masinloc in Zambales.

Senatorial candidates Alejano, Diokno, Gutoc and Hilbay attempted to visit Scarborough Shoal in West PH but was allegedly prevented by Coast Guard citing “national security” as reason, vows to bring the fight against China to the senate if elected. #Halalan2019 pic.twitter.com/XE8n8L0zYu

— Ron Gagalac (@rongagalac) April 8, 2019

Masinloc is home to a community of fishermen allegedly harassed by Chinese coast guard personnel at the resource-rich shoal.

Senatorial candidates Gary Alejano, Chel Diokno, Samira Gutoc, and Florin Hilbay were supposed to travel by boat to Scarborough Shoal to see firsthand the situation of the fishermen and how China has been controlling the area.

But the Philippine Coast Guard (PCG) denied the candidates' requests to visit the shoal, citing "national security."

On Tuesday, the maritime law-enforcement agency added that the opposition candidates did not seek clearance to visit the contested area in the first place.

"Otso Diretso candidates did not ask permission from PCG, that's the reason why they were not allowed to go to Scarborough Shoal," PCG spokesperson Armand Balilo told ANC.

The candidates and their supporters instead went to the shoreline and planted a Philippine flag to protest China's intrusions.

"Ngayon maliwanag na walang makapunta sa Scarborough, walang makapag-document, so that this administration can paint a very beautiful picture," said Alejano.

(It is clear now that no one can go to Scarborough, no one would be able to document, so that this administration can paint a very beautiful picture.)

Diokno said the disregard of the administration on Filipinos' rights in the disputed areas of the West Philippine Sea will have a long-term negative effect.

"'Yong mga susunod na henerasyon ng mga Pinoy ay maapektuhan tayong lahat. Ang daming kayamanan, natural resources na andiyan na inaagaw nila," he said.

(The next generation of Filipinos, we will be affected. There are so many natural resources there that they are stealing.)

The candidates also challenged President Rodrigo Duterte to fulfill his campaign promise of riding a jet ski in the disputed waters.

Senatorial candidates Diokno, Gutoc, Alejano and Hilbay challenged Pres. Duterte to fulfill his 2016 campaign promise to ride a jetski and fight for the country’s sovereignty against China. #Halalan2019 pic.twitter.com/e0eLctz6uy

— Ron Gagalac (@rongagalac) April 8, 2019

Some fishermen also aired their concerns to the candidates.

"Hindi po pinakikinggan ng gobyerno ang mga hinaing namin mga mangingisda," said Nards Millanes.

(The government does not listen to the concerns of fishermen like us.)

"Malaya na raw pero hindi po ganoon kalaya. Mga Filipino fishermen para pa ring mga magnanakaw sa pangingisda," said Leonardo Cuaresma.

(We were told that it was free but it is not as free as they say it is. Filipino fishermen are still like thieves when fishing.)

"Hindi barter ang nangyayari doon kundi pambu-bully ng China," he added.

(It is not barter that is happening there but bullying by China.)

There had been reports last year of an emerging "barter" system between Filipino fishermen and Chinese coast guardsmen, but it was only this year that the Filipinos lamented that they were on the losing end of this system.

Duterte earlier said he may raise China's alleged harassment of Filipino fishermen in Scarborough Shoal when he visits Beijing this month for the Belt and Road Forum for International Cooperation.

• Duterte may raise Scarborough Shoal harassment during China visit - Panelo