The Kenyan army says it has killed dozens of al-Shabab militants since launching an incursion into Somalia several days ago.

Army spokesman Emmanuel Chirchir told reporters Wednesday that 73 al-Shabab fighters have died in clashes with Kenyan forces. He said there have been no casualties on the Kenyan side.

There is no independent confirmation of the casualty figures.

Kenyan forces are reported to be in the Gedo and Lower Jubba regions of southern Somalia, as part of what the government calls a “pursuit” operation against al-Shabab. Kenya accuses the militants of kidnapping several foreigners on Kenyan territory — an allegation al-Shabab has denied.

France's foreign ministry said Wednesday that one of the kidnapping victims, French national Marie Dedieu, has died.

French officials who had been negotiating for her release said unspecified contacts informed them of her death. Officials say Dedieu probably died because she was not given required medication.

Dedieu was in her mid-60's and used a wheelchair, which the kidnappers did not take with them.

Unidentified gunmen kidnapped Dedieu from her private beach home in northern Kenya on October 1.

In the Somali capital Mogadishu on Tuesday, Kenyan and Somali government officials pledged to carry out “coordinated pre-emptive action” against “armed elements” that threaten both countries. The agreement appeared to limit Kenyan military action to Somalia's Lower Jubba region.

The Kenyan military forces have faced heavy rains and muddy terrain since advancing into Somalia.

Meanwhile, a Kenyan security minister says the government will conduct a sweep to catch suspected al-Shabab and al-Qaida sympathizers in Nairobi.

Speaking to parliament Wednesday, Internal Security Assistant Minister Orwa Ojodeah said al-Shabab is like a big animal with its tail in Somalia and its head in Kenya. He promised a massive operation against the group's supporters.

Al-Shabab is fighting to topple the Somali government and set up an strictly Islamic state. It once controlled most of Mogadishu but has been pushed back by government and African Union forces.

The militants have threatened to attack targets inside Kenya unless the Kenyan government withdraws its troops from Somalia.

Kenyan police stepped up security measures after al-Shabab promised on Monday to attack Kenyan targets unless the government withdraws its troops from Somali territory.

Al-Shabab has denied responsibility for the abductions, and has called on Somalis to defend against what it says are Kenyan “aggressors” and “occupiers.”