MOSCOW, Jan 26 (Reuters) - Russia said on Friday it believed separatist Chechen rebels were still using a gorge in Georgia as a hideout, reviving what could be a new irritant to relations that are already near rock bottom. In the past Russia has accused Georgia of turning a blind eye to Chechen rebels in its remote Pankisi Gorge. "We have information that a certain number of members of illegal armed groups are still present in the Pankisi Gorge," Interfax news agency quoted border official Lieutenant-General Anatoly Zabrodin as saying. "Even today we cannot rule out the threat that members of illegal armed groups could breach the border from the Georgian side," said Zabrodin, who heads the border protection directorate of the border guards sevice. The Pankisi Gorge is a heavily wooded slither of north-east Georgia from where mountain passes lead into Chechnya. Many of its inhabitants are ethnic Chechens. Before 2003, Moscow complained bitterly to Tbilisi that Chechen fighters fleeing Russian troops were slipping across the border into the gorge. International observers said Russia at one point launched air strikes on the gorge. The problem subsided after Georgia mounted a police and army operation to flush out Chechen rebels. The latest row broke out late last year when Georgia deported four Russian officers it accused of spying. Moscow responded by severing air, road and rail links to Georgia. On Thursday, Tbilisi said it had detained a Russian citizen who tried to sell highly enriched uranium to law enforcement officials posing as radical Islamists. Moscow said Georgia was trying to make political capital out of the case.