The seven French nationals seized in northern Cameroon earlier this week have been found in northern Nigeria and are with Nigerian authorities, French television BFMTV reported on Thursday.

The French captives were unharmed and abandoned in a house in the town of Dikwa where they were found, BFMTV cited military sources as saying.

But France's minister for veterans' affairs Kader Arif told parliament on Thursday that there was no official confirmation that they had been released, according to media reports.

So far, no group has claimed responsibility for the kidnapping. French authorities said the Islamist Boko Haram cell was likely to be behind the incident.

The hostages, including four children, were captured on Tuesday by a group of armed men on motorbikes near the Waza national park and Lake Chad where Westerners often visit during holidays.

French foreign ministry on Wednesday urged French nationals to leave northern Cameroonian area "as soon as possible."

French Defense Minister Jean-Yves Le Drian on Wednesday said the abduction was not linked to the country's ongoing military operation in Mali.

However, following its military commitment in Afghanistan and Mali, France has became a top target of Islamist extremists who warned French safety was at risk "wherever they find themselves in the Muslim world."

Seven French expatriates were still in the hands of al-Qaida-linked groups in the Sahel region.