By Abdoulaye Massalatchi NIAMEY, June 28 (Reuters) - Nomadic rebels in northern Niger have handed 30 wounded government soldiers taken prisoner during a raid on a Saharan military outpost a week ago to the Red Cross for medical help, a rebel spokesman said on Thursday. The Niger Movement for Justice (MNJ) killed 15 soldiers and took dozens hostage last Friday in a dawn attack on two army companies in Tazerzait, a remote settlement around a well in the Sahara desert near the Algerian and Malian borders. Thirty of the most seriously wounded captives had been freed and handed over to Red Cross medics for treatment, MNJ spokesman Seydou Kaocen Maiga told Reuters by telephone from Paris. "We freed them. They're in the hands of the Red Cross who are taking them to the town of Arlit to be treated," he said. The International Committee of the Red Cross said it had two teams in the area but that it was unable to confirm the number of injured as the operation was ongoing. "We were asked to go to take care of severely wounded people so we sent a surgical team," said Anna Schaaf, a Geneva-based spokeswoman for ICRC's operations in Africa. "We are just about to find out now what the state of these people is, how many they are, what we can do to help," she said. Northern Niger has long been a hotbed of dissent, largely beyond government control, full of disillusioned, unemployed youths and awash with arms left over from an uprising by Tuareg, Arab and Toubou nomads in the 1990s. Most of those rebel groups accepted peace deals in 1995 but the MNJ says the government has not lived up to its promises, failing to integrate former fighters and leaving the north economically marginalised and rife with insecurity. It has stepped up attacks on military targets, raiding the airport of Agadez -- the northern region's main town, popular with tourists -- earlier this month in a bid to destroy military surveillance planes. Despite mineral riches including iron ore, silver, platinum and titanium, Niger is one of the poorest states on earth. The MNJ says local communities should have more control over its natural resources, particularly northern uranium mines which are being exploited by Chinese and other foreign firms. At least 33 soldiers have been killed in the north since the MNJ launched its campaign in February. But President Mamadou Tandja's government refuses to recognise the group, saying the attackers are drug traffickers and common criminals. The former French colony's Democratic and Social Convention (CDS), the second biggest political party in the governing coalition, increased pressure on Tandja to negotiate late on Wednesday, calling on him to set up a team of mediators. (Additional reporting by Nick Tattersall in Dakar)