Swiss police have arrested two Tunisians suspected of links to the fatal stabbing of two young women in the French city of Marseille this month, Swiss media reported.

The Tunisians, both asylum seekers, were arrested on Sunday in Chiasso, near the Italian border, after an international warrant was issued for their arrests over suspected links to Ahmed Hanachi, who killed two women in Marseille on October 1, Swiss news agency ATS and several other media reported.

Federal police spokeswoman Cathy Maret confirmed to AFP that two asylum seekers had been arrested in Chiasso, in Switzerland's Italian-speaking Ticino region, after receiving information that "they could represent a threat to Switzerland's domestic security".

Ms Maret said they were arrested at the migrant registration centre in Chiasso.

But she did not confirm their nationalities nor that they were suspected of being linked to the Marseille attack. In addition she would not confirm whether an international arrest warrant had been issued.

"We are in the process of verifying their identities," she said.

Swiss news agency ATS also scaled back its initial reporting, which had sourced the nationalities of those arrested and their suspected Marseille link to federal police, saying only that two people had been arrested on suspicions of "links to terrorists activities abroad".

ATS meanwhile cited Italian media reports indicating that Swiss regional police had made the arrests based on information from Italian authorities.

And according to Swiss regional daily Ticinonews, the two men were Tunisians in their 30s who had arrived in Ticino a few days before they were detained.

The news comes as one of Hanachi's brothers, Anis, was arrested Saturday night in Italy, after French authorities issued an international arrest warrant.

Another one of his brothers and a sister were detained in Tunisia late last week and have been questioned by anti-terror investigators there.

ISIL has claimed responsibility for Hanachi's attack, but French investigators have not yet found evidence linking him to the jihadist organisation.