VLADIKAVKAZ, January 9 (RIA Novosti) - Georgian truck drivers transporting tangerines, who have been blocking a border crossing to Russia for several days after being denied entry, have voluntarily unblocked the border, frontier guards said Tuesday.

More than 60 trucks traveling from Georgia closed off the Transcaucasus Highway four days ago in protest against Russian authorities' refusal to let them into the country. Many of them had been stranded on the border for more than two weeks.

The Russian sanitary watchdog said the trucks had failed to produce the required documents, and added that Moscow had banned imports of Georgian fruit and vegetables in December 2005.

A source in Russian law enforcement agencies said earlier that the drivers had been aware of the ban, but had attempted to bring their freight into Russia regardless.

The incident is the latest blow to relations between Russia and Georgia, which have hit new lows in recent months since the brief detention in Tbilisi of four of Russian officers on espionage charges in September 2006, a move that sparked a furious diplomatic row. Russia has since maintained a ban on transport and postal links with its southern neighbor, and has deported hundreds of Georgian nationals.

Since coming to power on the back of the 2003 "rose revolution", Georgia's U.S.-educated leader Mikheil Saakashvili has pursued a course toward closer ties with NATO and the European Union, irritating Moscow and straining bilateral relations.