Four more people have been arrested as part of the investigation into last month's theft of precious jewellery at the Louvre Museum, the Paris prosecutor's office says.

Two men, aged 38 and 39, and two women, aged 31 and 40, were arrested on Tuesday. They are all from the Paris region.

Among them is thought to be the last member of a four-man gang that allegedly carried out the daylight heist. The other three suspected thieves have already been arrested and charged, officials say.

Police now have up to 96 hours to question them. No trace has so far been found of the stolen jewels - worth €88m (£76m; $102m) - which were taken on 19 October.

Four people have already charged over the heist - three men and a woman, who also live in the Paris region. A 38-year-old woman was charged earlier this month with complicity in organised theft and criminal conspiracy with a view to committing a crime.

Separately, a man, aged 37, was charged with theft and criminal conspiracy. These two suspects, who have not been named publicly, have denied any involvement.

The heist happened when the group of four men used a stolen vehicle-mounted mechanical lift to gain access to the Galerie d'Apollon via a balcony close to the River Seine.

The men used a disc cutter to crack open display cases housing the jewellery. They were inside for four minutes and made their escape on two scooters waiting outside at 09:38, before switching to cars.

Security measures have since been tightened around France's cultural institutions, and the Louvre has transferred some of its most precious jewels to the Bank of France.