An Egyptian criminal court has sentenced to death 10 alleged supporters of the now-outlawed Muslim Brotherhood group in connection with charges of killing a senior judge's security guard outside Cairo.

The court on Thursday said that it was referring the ruling to the Grand Mufti, the country's top Islamic authority, for his non-binding opinion on the matter — a requirement under Egyptian law.

The charges stem from the February 2014 killing of a security guard to a senior judge, Hussein Kandil, in the Nile Delta province of Mansoura.

The rulings can be appealed.

Since the 2013 ouster of Islamist president Mohamed Morsi, thousands of his supporters and loyalists have been jailed and hundreds sentenced to death in mass trials that had sparked international condemnation. The former leader himself was sentenced to death last month over charges including murder and kidnapping during a 2011 mass jailbreak.

The same court in Mansoura on Thursday sentenced four Islamists to death and 9 others to life in jail over violence-related charges dating back to protests in August 2013, following the violent dispersal of two protest camps by Morsi loyalists, a judicial source said.

The four handed down death sentences, as well as one who received life imprisonment, were present during the court hearing. Eight of the nine others are on the run.

The accusations include murder, attempted murder, possession of arms and belonging to a terrorist group, in reference to the now-banned Muslim Brotherhood.