Malawi government has asked United Nations (UN) Secretary General Ban Ki-moon to mediate the decades-long border dispute with Tanzanian over Lake Malawi believed to have oil deposits.. In the standoff Tanzania is claiming half of the Lake which is called Lake Nyasa in Tanzania. But Malawi claims the entire Lake basing on 1890 Anglo-German treaty also known as the Heligoland which put the border line on the shores of Lake Malawi. The treaty was later reaffirmed by the Organization of Africa Unity, [now African Union], when the country gained its independence in 1964. But Tanzania rejects colonial era agreements as permanent and argues international law including (1982 maritime treaty) supports sharing common bodies of water by bordering nations. Chiume: Asks UN chief to mediate On her return from the UN conference in United States of America, Malawi President Joyce Banda announced that Malawi has pulled out from talks with Tanzania on the matter following reports that Tanzania has launched a new map that shows the border line on the middle of Lake Malawi. But in latest remarks, Malawi Foreign Affairs Minister Ephraim Mganda Chiume said: The Tanzanians want (the Southern Africa Development Community) SADC to mediate but we have asked the United Nations Secretary General to mediate. Chiume, who led a team of Malawian government officials on a tour of the border district of Karonga Thursday where he assured residents of government protection following the simmering tensions, said the border wrangle will be well handled. He said Malawi has not given up hope that an amicable solution would be found. Malawis Principal Secretary in the ministry of Foreign Affairs and International Cooperation Patrick Kabambe said Tanzanian authorities had sent a letter responding to issues raised by the Malawian government that caused suspension of dialogue between the two countries over the lake. I can say the door on dialogue on the matter is still open, he said. However speaking on Malawis privately owned FM radio, Zodiak Broadcasting Service Tanzanias High Commissioner to Malawi, Patrick Tsere, said as far as he is concerned, the lake still belongs to Malawi and Tanzania until the border dispute between them is resolved. But Tanzanias Foreign Affairs minister, Bernard Membe, speaking at news conference in Dar es Salaam challenged Malawi President on her decision to take Tanzania to the International Court of Justice (ICJ) saying despite being a member of the court Tanzania has not ratified the ICJ clause that binds countries to the courts compulsory jurisdiction, without which the court has no powers to hear cases from nations that do not recognize its jurisdiction. Malawi signed the clause in 1966. A renowned University of Malawi historian Simbarashe Mungoshi told Nyasa Times recently that there is possibility that the ICJ would rule in favour of Malawi considering its previous ruling on border dispute between Botswana and Namibia over the ownership of one island called the Kisikili which is on the River Okavango. When these two countries could not resolve the dispute among themselves, they took the matter to the ICJ and it ruled in favour of the 1890 Treaty of the Heligoland. So we have a precedent here ICJ took recourse to the 1890 Heligoland treaty to decide the ownership of the Kisikili Island. So I think Malawi is right in taking the matter to the ICJ, he said. Mungoshi said he found rather crooked that some people in Tanzania could argue that there is international maritime treaty which requires states bordering water body to have an equal share of the waters. I know that treaty it is of 1982. But the treaty goes on to say that in the event that there was an agreement prior which stated otherwise, the prior agreement should be the one to define the boundary. So in this case the prior agreement in on this the treaty of the Heligoland, he says. Mungoshi says history tells that Tanzania was one of the first countries in 1963 to ratify the Organization of African Union charter which among other things recommended that upon independence the boundaries should remain there as was before independence. The 29, 600 square Kilometre Lake is a home to about 1,000 endemic species of fish. It sustains nearly 10 million people in Malawi, Mozambique and Tanzania. UKs Surestream Petroleum was given a licence by Malawi to explore hydro-carbons in the Lake Malawi basin. But published reports indicate that President Joyce Banda is wooing US oil giant, Chevron, to come to Malawi to invest in oil exploration on Lake Malawi.