An Al-Qaeda offshoot holding seven Algerian diplomats hostage in lawless northern Mali said Sunday it had broken off negotiations for their release.

The hostages, a consul and six colleagues, were seized on April 5 in Gao, northern Mali, as several armed groups descended on the region following a coup in the capital Bamako.

"We have broken off negotiations for the release of the Algerian hostages," the Movement for Oneness and Jihad in West Africa (MUJAO) said in a statement sent to AFP.

"Algeria is trying to stall for time. Our movement is ready to take responsibilities if it tries to free these hostages by force.

"We are maintaining our claims. The Algerian government's intermediaries have received our message," added the statement signed by its spokesman Adnan Abu Walid Sahraoui.

The kidnappers have demanded 15 million euros for the release of the Algerians. When negotiations failed on May 8, they gave a 30-day deadline for Algiers to fulfill the demands before they would kill the hostages.

In June, they said progress was being made in the negotiations.

The group is also holding three European aid workers -- a Spanish man, a Spanish woman and an Italian woman -- who were captured at the end of October 2011 from a refugee camp in western Algeria.

The jihadists want 30 million euros as price for their release.

On Sunday, the group also said that more "fighters" were joining their "pursuit of jihad."

"Our Mauritanian, Tunisian, Malian and Sahrawi brothers turned out in large numbers to support jihad," the group said, without giving figures.

Together with Al-Qaeda in the Islamic Maghreb (AQIM) and Ansar Dine, MUJAO is one of three Islamist groups that currently controls northern Mali, which they seized with the help of Tuareg rebels.