KHARTOUM - Armed men kidnapped 31 Darfuris on their way to a conference for people displaced by the Sudanese region's decade-long war, the international peacekeeping mission in the area said on Monday.Darfur has been torn by conflict since 2003 when mainly non-Arab rebels took up arms against the Arab-led government, accusing Khartoum of politically and economically marginalizing the region.Violence is down from its peak in 2003 and 2004, but a surge has forced more than 130,000 people to flee their homes since the start of the year, according to the United Nations.The joint African Union-United Nations peacekeeping mission (UNAMID) said it was escorting three buses carrying the Darfuris when it was stopped by a "large unidentified armed group in military uniforms and seven jeep-mounted guns" on Sunday.