The Paris prosecutor's office says four men are facing preliminary charges after being arrested on suspicion of links to a gunman involved in France's deadliest terrorist attacks in decades.

The prosecutor's office said in a statement that five others arrested in the investigation were released without charge early Tuesday.

The four remaining suspects, all men in their 20s, will appear before an investigating judge later Tuesday. No other details were immediately available.

No one has been charged in the attacks Jan. 7-9 on satirical newspaper Charlie Hebdo, a kosher market and police. Twenty people were killed, including the three gunmen, who claimed allegiance to al-Qaida and the Islamic State group.