U.N. Secretary-General Kofi Annan on Wednesday urged Eritrea to lift a ban on U.N. helicopter flights along the border with Ethiopia, warning that the decision could only add to tensions between the two nations, AP reported. Annan said the ban, which went into effect Wednesday, goes against the fundamental right to freedom of movement for all U.N. peacekeeping missions. There are some 3,500 troops and police monitoring a buffer zone along the border separating the Ethiopian and Eritrean armies. U.N. spokesman Stephane Dujarric said U.N. helicopters had not been given permission to fly and peacekeepers were obeying the ban. On Tuesday, the U.N. Security Council, meeting at Annan's request, adopted a statement that warned the two Horn of Africa nations not to reignite their border war. The two nations fought a 2½-year conflict that ended after a December 2000 peace agreement. The council called on both countries «to show maximum restraint and to refrain from any threat of use of force against each other.» Annan echoed the council's remarks, saying the ban on helicopter flights by the peacekeepers could «exacerbate the existing suspicions at the border area and create instability.»