President Rodrigo Duterte's threat to send to jail critics who would file an impeachment complaint against him was just an "expression of righteous indignation," Malacanang said on Monday.

In a press briefing, Presidential Spokesperson Salvador Panelo said Duterte was just "pissed off" with those who could not understand over his stance towards China as far as the South China Sea issue is concerned.

"That was an expression of righteous indignation. He cannot even understand why these critics and detractors cannot visualize what he’s doing for the country. He was pissed off by that," he said.

He said US had failed to stop China from building at the disputed South China Sea and now his critics wanted him to do something about it.

"They’re really looking for trouble," he said.

Duterte has been criticized for his seeming stance to allow Chinese to fish within the Philippine exclusie economic zone to the detriment of the Filipino fishermen.

His critics have said Duterte could be charged for culpable violation of the Constitution and betrayal of public trust, both grounds for his impeachment.

But the President, who apparently became furious, in a recent interview, said he would send to jail those who would initiate his impeachment. Celerina Monte/DMS