By Mabvuto Banda | LILONGWE (Reuters) Malawi has cut off dialogue with Tanzania in a long-time territorial dispute concerning Lake Malawi, thought to sit over highly coveted oil and gas reserves. Malawi claims sovereignty over the entirety of Africa's third largest lake, while Tanzania says 50 percent is part of its territory. The row, which goes back half a century, could worsen if significant oil and gas discoveries are made. Malawian President Joyce Banda said late on Tuesday she believed Tanzania had raised tension by moves such as alleged intimidation of Malawian fishermen on the lake, which also borders on Mozambique. "I was of the view that the matter is being resolved through dialogue but now it looks bigger than I thought. While in New York, I wrote them (Tanzania) telling them that there is no point going on with the dialogue," Banda told a news conference in Lilongwe. Tanzanian foreign ministry officials were not immediately available for comment on Banda's remarks. The Malawian leader also cancelled a planned visit to Tanzania this month for talks on the dispute. ENDELEA @ REUTERS My Take: Kuna kitu ambacho kinaendelea na Malawi inaonekana wanajipanga vizuri zaidi. Ina maana TZ itabidi iwabembeleze. Miye nilitoa ushauri wangu; Tanzania ianze utafiti upande wake wa Ziwa Nyasa tuone Malawi itafanya nini? Na kwenda ICA hatuendi.