The first bomb, believed to have been remote controlled, went off in the Eredvi village two meters from a highway where a column of Georgian police vehicles was passing. A third car was also hit, and two policemen were wounded.
Earlier in the day, an explosion hit the Ergneti village near a school, but no injuries were sustained.
South Ossetia and Abkhazia, another rebel province, broke away from Georgia in the early 1990s following the collapse of the Soviet Union. Between 10,000 and 30,000 people were killed in the Georgian-Abkhazian conflict and some 3,000 in Georgian-South Ossetian hostilities.
Georgia is looking to regain control over the two de facto independent republics, and accuses Russia of trying to annex them.
Relations between Moscow and Tbilisi have drastically deteriorated since the Kremlin called for closer ties with Abkhazia and South Ossetia in mid-April.
Russia has also increased the number of its peacekeepers in Abkhazia but said the rise was within the limits of agreements on troop numbers signed by the Georgian leadership.
