Niamey - Five soldiers were killed and four others missing following an attack on Tuesday in southwest Niger close to the border with Mali, a security source told AFP."This terrorist attack against the town of Banibangou killed five soldiers, injured three and four others were reported missing," said the source, who requested anonymity.A Niger official also confirmed the attack which happened around 4:00am. The interior ministry said two of the attackers were killed in the raid, and that 26 others were arrested with weapons and ammunition. The ministry, in a statement, provided a toll of four injured soldiers.Niger's long, porous borders make it vulnerable to the armed violence plaguing its neighbours, such as Mali, Nigeria and Chad.Last month 22 of Niger's soldiers were killed when armed men who had travelled from Mali launched an attack on a refugee camp in the western town of Tazalit.Northern Mali fell under the control of Al-Qaeda-linked jihadist groups in 2012. A French-led military intervention pushed them out, but swathes of the country remain out of government control and awash with armed groups.Niger also faces constant raids in the south by Nigeria-based jihadist group Boko Haram.A US aid worker was abducted from his home in central Niger last month.