Both the Inter-Governmental Authority on Development and the East African Community have joined the international fraternity in urging restraint in the rising tensions between the Horn of Africa arch-rivals,  Ethiopia and Eritrea.The calls for a peaceful resolution of the standoff between the two countries come in the wake of Ethiopian troops crossing the border into Eritrea for the second time on Saturday in what is said to be in hot pursuit of rebels.Both regional blocs are understood to have reached out to both countries through their embassies in Nairobi, even as the UN Secretary-General Ban Ki-moon joined the growing chorus urging Ethiopia and Eritrea to avoid any action that could escalate tensions between the two neighbours. "The Secretary-General has urged both sides to exercise maximum restraint,” Mr Ban’s spokesperson, Martin Nesirky, said in a statement sent to media houses. "He calls on Ethiopia and Eritrea to resolve their differences through peaceful means and to avoid any action that could lead to an escalation of tensions,” he added. Tensions persist between the two countries, which fought a bloody border war that ended in 2000 with the parties agreeing to abide by the ruling of the Eritrea-Ethiopia Boundary Commission. However, Ethiopia’s rejection of the decision reached by the commission in 2002 stalled the physical demarcation of the border in 2003. The Secretary-General urged both parties to respect each other’s territorial integrity. Ethiopia’s raid of the rebel bases inside Eritrea has not come as a complete surprise to observers in the region. Addis Ababa has routinely accused Eritrea of hosting and training separatist fighters opposed to the government of Prime Minister Meles Zenawi.In January this year, Ethiopia reacted angrily to an attack that killed five Western tourists. It also blamed the same Afar rebel movement for an earlier kidnapping of Westerners in its northern Afar region in 2007.IGAD is said to be closely monitoring the situation amid growing fears that the dispute between the two bitter rivals could find its way into Somalia, which the region has struggled so hard to stabilise. The two countries have been accused of taking their dispute to Somalia where they back different factions in the beleaguered country.The two neighbouring countries, which share a history, accuse one another of support separatist groups and terrorist groups against each other.Addis Ababa has; however, succeed in portraying Asmara as the villain in their long drawn border and ideological conflicts. Besides Ethiopia is valued partner of the United States government in it war on terror.The last week’s attack by the Ethiopian government is the first since the end of the 1998-2000 war that killed an estimated 80,000 people and which still festers simply because the border dispute that triggered the conflict remains unresolved.