Members of a radical Islamic group in northern Mali are claiming to have executed one of the Algerian diplomats they kidnapped five months ago, when their fighters raided the Algerian consulate in the city of Gao.

The information could not be independently verified, and the Algerian Foreign Affairs Ministry said they are investigating the rebels' claim.

Islamist leader Oumar Ould Hamaha told The Associated Press by telephone late Saturday that that the Movement for Unity and Jihad in West Africa (known by the French acronym MUJAO), had executed the diplomat in order to teach Algeria a lesson. The group had demanded that Algeria, Mali's northern neighbor, release the members of their group who had recently been arrested.

"We did this so that Algeria learns a lesson and understands that when we give an ultimatum, they need to take us seriously," said Hamaha. "And so that other countries know that when give an ultimatum in regards to their hostages, they need to act."

In Algeria, the ministry said Sunday that a press release written by the MUJAO announcing the execution "is currently the subject of testing needed to ensure its authenticity."

In a statement released through the official Algerian news agency APS, the ministry was quoted as saying that the families of the hostages in northern Mali had met with the Ministry of Foreign Affairs' secretary general on Saturday morning "who reminded them specifically that contact with the kidnappers was not broken. "

The ministry added that the crisis "is being dealt with openly and (we) will not fail to inform the families and the public of any new national development."

MUJAO is a relatively new group active in the deserts of northern Mali, but they are known to be allied with al-Qaida in the Islamic Maghreb, or AQIM, the local al-Qaida franchise which has kidnapped over 50 foreigners since 2003, most of whom were released in exchange for hefty ransoms. AQIM has, however, executed a few of the hostages, including a British man, as well as an elderly French national.

Saturday MUJAO seized control of the strategic town of Douentza, significantly increasing the territory held by Islamist extremists and moving much closer to government-held territory in central Mali.

Early Saturday morning, a convoy of pickup trucks carrying bearded men entered Douentza, located about 500 miles (800 kilometers) northeast of the capital, Bamako. While far from the capital, Douentza is only 120 miles (190 kilometers) from Mopti, which marks the line-of-control held by the Malian military.

The Malian military lost control of the northern half of the country in April, including Douentza. But until now, the Islamists didn't control the town either, relying instead on an agreement with the local militia, which patrolled the area.

Until March, Mali was considered one of the most stable countries in the region, with a 20-year history of holding democratic elections. That changed in a matter of hours on March 21, when renegade soldiers overthrew the elected government, installing themselves as the new leaders by the next morning. The coup plunged the nation into disarray, providing an opening for the Islamists in Mali's far north.

The extremists have since made huge gains, taking the entire northern half of Mali, including Timbuktu, and causing some 440,000 people to flee, according to the United Nations.

Since April, however, the unofficial line of control between the government-controlled south and the rebel-held north had not shifted. Saturday's development indicates the Islamists may have ambitions beyond the north, which unlike the more developed south, is sparsely populated and largely comprised of desert.

Asked if they planned to hold Douentza, Hamaha said: "We never retreat. Even if we don't advance any further, we will not go backward."

However, when asked specifically if they planned to try to take Bamako, he said that they would only advance on the capital if the Malian military provokes them.

"If ever the Malian military attempts to take back the north, then in less than 24 hours, we will take the quasi-totality of Bamako and the black flag of the Islamists will fly over Koulouba," he said, mentioning the name of the presidential palace in Mali's capital.


Associated Press writers Rukmini Callimachi in Dakar, Senegal and Aomar Ouali in Algiers contributed to this report.