Two men suspected of helping the gunman who killed two people in attacks in Copenhagen last month have been detained until next Thursday.

Prosecutor Stig Fleischer said the pair would reappear before a judge next week for an extension of their detention at the same time as three other men also are suspected of aiding Omar El-Hussein.

"That way we have them all together," Mr Fleischer said.

A 30-year-old man is suspected of helping El-Hussein getting rid of the M95 assault rifle he used to kill a bystander outside a free-speech seminar before spraying the entrance with 27 bullets on February 14.

The suspect was arrested on Thursday. Denmark's TV2 said he has "clear relations" to an inner-city immigrant gang in Copenhagen that El-Hussein had ties with.

A 25-year-old man helped 22-year-old El-Hussein get rid of undisclosed objects he used nine hours later when he attacked Copenhagen's main synagogue and killed a Jewish guard, according to Mr Fleischer.

After the preliminary charges were read, the rest of the hearing was held behind closed doors and details were not made public. None of the five suspects, who have pleaded innocent, can be named under a court order.

Five officers were wounded in the attacks, and El-Hussein was later killed in a police shootout.