* Angolan ambassador in Congo Republic denies troops held
* Incident underscores tensions surrounding oil-rich Cabinda
A detachment of Angolan troops crossed into neighbouring Congo Republic earlier this week and has detained a group of Congolese soldiers, a senior Congolese officer said on Thursday.
Angola's ambassador in Brazzaville said he was not aware of any Angolan troop movements inside Congo Republic and denied that his country's army was detaining Congolese soldiers.
The incident highlights tensions around Angola's oil-rich Cabinda enclave, which is separated from the rest of Angola and surrounded by Congo Republic and Democratic Republic of Congo.
Cabinda is home to the FLEC rebellion, which has fought a low-intensity guerrilla war against Luanda for decades.
The Angolan soldiers entered Congo's Kimongo district from Cabinda on Sunday, Colonel Christian Sansa, a senior commander with Congo's gendarmes deployed in the area, told Reuters.
"They claim they are in their own country's territory. We think it's a problem of their unfamiliarity with the borders," he said.
Sansa said Congo had deployed soldiers to the area after learning of the incursion but they were quickly subdued by the Angolan forces.
"Our soldiers were surrounded by the Angolan soldiers, and as we speak there has been no change in that situation," he said.
French broadcaster RFI reported that as many as 40 Congolese soldiers had been detained by the Angolans. Citing anonymous local sources, RFI said Angolan troops were controlling five positions in the area.
Angola, which possesses one of the region's most capable militaries, has in the past pursued the separatist rebels beyond its borders, notably in Democratic Republic of Congo.
Angolan defence and foreign ministry officials did not respond to requests for comment.
Angola's ambassador to the government in Brazzaville told journalists on Thursday that he was still seeking information on what, if anything, had happened along the border. However, he denied that Angolan soldiers had detained Congolese personnel.
"It's not true. It's false. But you know that at any border there is always friction either among the population or with the services charged with monitoring the border," said the ambassador, Fernando Pedro Mavunza.
Angolan President Jose Eduardo dos Santos has recently said he wants to help secure peace and stability in the region through diplomacy, rejecting for example calls for it to send soldiers to help quell the rebellion in eastern Democratic Republic of Congo.
"At the international level, the reality of the facts has shown that the use force or threats to do so is becoming a dangerous political culture which in no way contributes to end violence," dos Santos said in a state of the nation address on Tuesday.
Angola's last overseas military operation, a mission to reform the security sector in Guinea-Bissau, was cut short last year after the Bissau government asked the Angolans to leave.