President Rodrigo Duterte has ordered Pedro Aquino, Jr., president and chief executive officer of the Philippine National Oil Company (PNOC)-Exploration Corp. to submit his resignation for "loss of confidence," Malacañang said on Tuesday.

"The President's order is still in line, and pursuant to his anti-corruption campaign in the government, and underscores once again that there are no sacred cows under this Administration," said Presidential Spokesperson Salvador Panelo in a statement.

He did not mention why Duterte lost confidence in Aquino.

"We reiterate the directive of the President to all officials and employees of the government to undertake actions which are only pursuant to what the law provides in the performance of their official functions and desist from committing any act that are -- or may appear to be -- irregular, illegal or dishonest," added Panelo, also chief presidential legal counsel.

In a statement earlier, Senator Sherwin Gatchalian said Aquino was suspended for approving a memorandum of agreement with a Russian firm for the development of a multilateral cooperation in oil products and trading, and joint participation in oil refining without the permission from the board or from Energy Secretary Alfonso Cusi.

The suspension ''highlights the need for a clear policy direction for the entire PNOC family,'' said Gatchalian.

The DOE said earlier in the day that it would issue a statement regarding Aquino. As of press time, it has not yet released a statement. Celerina Monte/DMS