Two men have been arrested in connection with a mine explosion in Senegal’s southern Casamance region three weeks ago, which killed one worker with the International Committee of the Red Cross (ICRC) and injured three others.

Gendarmes arrested Mamadou Sane and Alassane Sane, respectively imam and chief of Lefeu village, 80 km north of the region's main city, Ziguinchor, on Thursday.

The men have been accused of orchestrating the planting of a mine on 1 September near the village Tandine. A jeep belonging to ICRC, which was working on health projects in the region, struck the mine. Jeanette Fournier, an ICRC international staff member, was killed in the explosion.

The Senegal army was believed to have been the target of the mine, according to aid workers. Since mid-August the army has been engaged in a major campaign throughout northern Casamance against a pro-independence faction of the Movement of Democratic Forces of Casamance (MFDC) rebel group.

“They have been arrested because they helped the rebels in planting the mine,” a police officer told IRIN. “We have interrogated several other villagers about this and it is only Mamadou Sane and Alassane Sane who have been detained.”

The Ziguinchor prosecutor, Saliou Mbaye, confirmed the arrest. No details of the charges or trial date were available on Friday.

However, a spokesperson for the MFDC in Ziguinchor denied the two arrested men were involved in the attack.

“The people they have arrested do not work with our movement,” the spokesperson said. “They have been arrested simply because the incident happened near their village. It is like that every time there is an incident like this.”

The vast majority of Casamance residents are not involved with the rebels, a small group with an estimated 300-1,000 fighters who have been battling the Senegalese government and different factions of their own movement for almost 25 years.

More than 15,000 people in Casamance are estimated to have fled their homes either inside Senegal or into neighbouring Gambia to the north since renewed fighting started in August.

Although local residents say all the rebel bases are situated in remote forest areas away from civilian villagers, many people said they fled anyway because they feared being mistakenly identified as rebels by the Senegalese army.

Hundreds of mines scattered around the south of Casamance close to the border with Guinea-Bissau are the deadly legacy of almost two decades of fighting there in the 1980s and 1990s. Aid agencies say both the rebels and Senegalese army still use mines.