KAMPALA, Aug 14 (Reuters) - Uganda's foreign minister was in Kinshasa on Tuesday for talks to defuse growing tensions after Democratic Republic of Congo troops shot dead a British oil worker on the border between the two countries. Congo says its soldiers were merely returning fire in the Aug. 3 battle with security guards working for Heritage Oil Corp, which Kinshasa says was carrying out illegal exploration in its half of Lake Albert. Foreign Minister Sam Kutesa flew to Kinshasa on the orders of President Yoweri Museveni, Kutesa's deputy said. "Though the president has made repeated attempts to talk to President (Joseph) Kabila in vain, government has decided to explore all diplomatic options available to avoid war," Henry Okello Oryem said. The Heritage incident followed the July 29 arrest of four Ugandan soldiers by DRC forces, who were later freed, and came six days before three Ugandan civilians were killed further south by a militia that crossed the frontier from DRC. Relations between Kampala and Kinshasa have been fraught for years, with Kampala regularly threatening to send troops across the border if no action is taken against a number of rebel groups based in lawless eastern DRC. The neighbours fought a 1998-2003 war involving five other countries scrambling for Congo's rich resources. Lake Albert, in east Africa's Great Rift Valley, is the focus of a new hunt for crude on a continent long dominated by West African oil sources. Heritage is exploring in two blocks on the Ugandan side of the lake and has found high grade crude in a well drilled this year. It also has concessions in Congo but has not yet had permission to start operations there, the government says.
