(Adds background) By Francis Kwera KAMPALA, Oct 3 (Reuters) - A crucial meeting between senior Congolese and Ugandan energy officials over oil was suddenly cancelled after Kinshasa withdrew its delegation, a Ugandan spokesman said on Wednesday. The meeting was called by Uganda to defuse tensions with Congo after two shootings in as many months along their border on Lake Albert -- an important new frontier in the search for oil in Africa. The talks to review a 1990 oil exploration and exploitation agreement between the two countries were due to start on Wednesday in the Ugandan capital Kampala. "The Congolese delegation has communicated to us and postponed the meeting indefinitely. They did not give us any reasons," Uganda Mineral and Energy ministry spokesman Matovu Kiwanuka said. Congolese officials said Oil Minister Lambert Mende Omalanga was unable to attend the planned meeting because of other commitments, but they did not elaborate. Uganda and the Democratic Republic of Congo are sitting on what prospectors believe could be oil reserves of up to one billion barrels in the Albertine Basin they share. Canada's Heritage Oil Corp <HOC.TO> and British-based Tullow Oil <TLW.L> are both drilling in concessions around the basin. In the most recent border shooting, last month, U.N. officials said six civilians were killed when Ugandan soldiers opened fire on a Congolese passenger boat on Lake Albert. But Uganda's military said two soldiers were killed, one from each country, in what it said was a gunfight during a dispute over an oil exploration vessel on the lake. The border row exposes longstanding suspicion on both sides stemming from Congo's 1998-2003 war, in which Kampala backed rebels trying to overthrow the Kinshasa government. (Additional reporting by Joe Bavier in Kinshasa)
