The two were arrested Tuesday after displaying posters on their Facebook pages that apparently incited people to set off firecrackers in every courthouse in the country Wednesday, Inspector General Khalid Abu Bakar said.
"They are being remanded for further investigation," he said in a statement.
Khalid did not say whether they were linked to a YouTube video that also threatened to attack courthouses throughout the country.
The video, posted Sunday, showed four masked men with a Malaysian flag behind them, while one denounced the judiciary for being used as a political a tool to manipulate democracy.