TBILISI/MOSCOW, August 12 (RIA Novosti) - President Mikheil Saakashvili urged Georgians to join a mass rally to display national unity outside parliament, amid what he has called an 'occupation' of most of Georgian territory.

Russian troops moved into the country on Monday as part of a peace enforcement operation to prevent further Georgian attacks on breakaway South Ossetia, blocking a central highway linking Georgia's east and west. Russia has conducted numerous air strikes against Georgian military targets.

Saakashvili said in a national address on Monday evening: "I want to show our unity to the entire world. I want everyone to tell our enemies that we will never surrender, will never give up our freedom and get down on our knees," he said.

Russia drove Georgian troops out of the devastated South Ossetian capital, Tskhinvali, on Sunday, two days after Tbilisi launched a major ground and air offensive to regain control of the pro-Russian region. Russia says 1,600 civilians, mainly Russian nationals, were killed in the Georgian onslaught, and that over 34,000 refugees have fled to Russia.

The Russian Defense Ministry denied international media reports on Monday that Russian troops were closing on the Georgian capital, Tbilisi, and had entered the Georgian Black Sea port city of Poti.

A ministry spokesman said Russian troops had withdrawn from the town of Senaki, near Georgia's other breakaway region, Abkhazia. A senior Russian peacekeeping official said on Monday that Russian aircraft had shot down two Georgian helicopters at the Senaki airbase.