France's foreign ministry says an elderly French woman kidnapped in Kenya earlier this month has died.

French officials who had been negotiating for the release of Marie Dedieu announced her death on Wednesday, although they did not give the circumstances or date of her death.

Unidentified gunmen kidnapped Dedieu on October 1 from her beach house in northern Kenya. Dedieu was in her mid-60's and used a wheelchair, which the kidnappers did not take with them.

Kenyan officials suspect that militants from the Somali insurgent group al-Shabab were involved in the kidnapping, as well as the recent abductions of a British tourist and two Spanish aid workers.

On Sunday, Kenyan authorities launched a military operation into Somalia to hunt down members of the al-Qaida-linked Islamist group.

The Kenyan military forces are facing heavy rains and muddy terrain as they advance into at least two regions of southern Somalia.

Kenyan troops are reported to be near the al-Shabab-controlled town Afmadow in Somalia's Jubba region, where residents are said to have been fleeing in fear of a battle.

Officials and witnesses told VOA on Tuesday that Kenyan troops, backed by helicopters, had also passed through the Somali border town of El-Waq and advanced to Somalia's Gedo region.

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.

A suicide car bomb on Tuesday killed at least five people and wounded nine others near Somalia's foreign ministry, where the high-level meeting was taking place. There has been no claim of responsibility for the attack.

Meanwhile, Kenyan police are stepping 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.”