At least two Rwandan soldiers in an attack by rebels who had crossed the border from the Democratic Republic of Congo, President Paul Kagame said on Friday.The Rwandan army blamed the December 9 assault in the country's restive east on Hutu rebel group, the Democratic Forces for the Liberation of Rwanda (FDLR)."A group arrived from DRC and attacked our positions, I think they killed two or three of our soldiers," Kagame said at a news conference."A number of them (the rebels) were killed and their bodies taken away by their friends in the DRC. We are seeking clarification and cooperation from the Congolese authorities," he added.The FDLR, set up in 2000, includes several leaders who took part in the 1994 Rwandan genocide, in which hundreds of thousands of ethnic Tutsis were slaughtered by the Hutu majority government.Eastern DRC has been a theatre of ethnic violence for 20 years, fuelled in part by the desire to control valuable mineral resources and farmland.The FDLR is regularly accused of atrocities on Congolese soil.Tensions are rising in the vast, unstable country ahead of the December 23 election when Congolese voters will choose a successor to President Joseph Kabila who has remained in power as a caretaker leader even though his second and final elected term ended nearly two years ago.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.