(UPDATES) THE Makabayan bloc on Wednesday filed a resolution urging the House of Representatives to investigate the smear campaign against Sinovac allegedly conducted by the Pentagon during the height of the Covid-19 pandemic, as reported by Reuters.

Reuters said the black propaganda employed social media accounts, some of which were later deleted by X (formerly Twitter).

"Such underhanded tactics by a foreign military power sowing disinformation in the Philippines are a brazen affront to our national sovereignty and the democratic rights of Filipinos to freely access truthful information vital to public health and safety," read part of House Resolution 1773.

"The spread of disinformation exacerbated by foreign actors like the US military directly contributed to difficulties in the Philippine government's pandemic response and vaccination efforts," it added.

The Makabayan bloc is composed of House Deputy Minority Leader and ACT Teachers Rep. France Castro, House Assistant Minority Leader and Gabriela Women's Party Rep. Arlene Brosas, and Kabataan Rep. Raoul Manuel.

"It is imperative that we ascertain the extent of the damage caused by this secret campaign and hold those responsible accountable. The Philippines was one of the areas targeted by this operation, and therefore, it is our duty to safeguard our nation's sovereignty and protect our people's health," Castro said.

On Wednesday, Senator Imee Marcos sought an investigation of the alleged US propaganda.

The senator filed Resolution 1052 on June 18 directing the Senate Committee on Foreign Relations, which Marcos heads, to conduct the inquiry.

Marcos said the reported anti-Sinovac vaccine and misinformation campaigns "gravely threaten national security issues and public health."

There is a need to verify if indeed the alleged campaigns were orchestrated by the US military, she said.