PARIS - Press freedom is under attack in France as three journalists face an inquiry over the leaking of a classified report on the use of French arms in Yemen, rights groups are warning.

The three journalists -- Geoffrey Livolsi and Mathias Destal from the Disclose website and Radio France's Benoît Collombat -- have been summoned to a hearing on Tuesday and Wednesday at the domestic intelligence agency DGSI, which is leading investigations into the leak.

The inquiry was 'an unacceptable attack on press freedom and the protection of journalists' sources', said a letter signed by 17 rights groups including Amnesty International, Human Rights Watch, the International Federation for Human Rights and Sherpa.

Investigative new media outlet Disclose obtained a military intelligence dossier, classified as confidential, dating from September 25 that details the French tanks, artillery and ships in Yemen.

The information 'is of essential public interest', the rights groups said, urging the French interior, army and foreign ministries to 'cease intimidation against the press and respect the secrecy of sources'.

The 15-page dossier, which Disclose published last April 15, details weapons sold to Saudi Arabia and the United Arab Emirates who have led a bloody campaign against Huthi rebels in Yemen.

Under pressure for years by rights groups over the sales, Paris has always insisted the arms are only used in defensive circumstances to deter attacks by rebels.

French President Emmanuel Macron last Thursday defended the arms sales to Saudi Arabia and the United Arab Emirates with a new shipment expected to leave from the northern port of Le Havre.

Some 10,000 have died in the Yemen war and millions have been forced to the brink of starvation.