Giorgi Mebonia, the governor of the Tsalenjikha district of Georgia, has been killed in an explosion close to the border with Abkhazia.
A Georgian villager also died in the attack and a police officer was injured, in the village of Mujava on Saturday, according to officials.
The Georgian interior ministry told Al Jazeera that Mebonia's car was hit by a explosive device and the convoy was fired at, but it is not known who fired the shots.
A Georgian police officer travelling with the group told Russian television that shots came without warning "from the Russian side".
Matt Siegel, an Associated Press journalist, told Al Jazeera: "The Georgians are saying that they have found an antenna from this device which indicates that it was remotely detonated.
"They have blamed the Abkhaz separatist government and the Russians."
Mebonia was with European Union monitors and police in the village on Saturday investigating a home which had reportedly been hit by three grenades the previous night.
"It is quite a dramatic development," Al Jazeera's Helena Bedwell, reported from the Georgian capital Tbilisi.
"In the bordering village ... the situation started heating up last night when according to the residents of this village said that they heard a series on gun shots and artillary coming towards the village ... And according to them it was not just Abkhazians but also Russians soldiers patroling the area.
"Right now the village is calm, EU monitors are controlling the situation."
Shota Utiashvili, an interior ministry spokesman, told the AFP news agency: "This was clearly aimed at the police because they knew the police would go there to investigate."
However, Steve Bird, a spokesman for the EU monitoring mission, said that it was too early to say who and what caused the explosion
"Its something for the Georgian police to investigate and that will take them some time to do," he said.
"We have no further information as yet as to the origin of the explosion, who might have been involved with it, I think it's too early to say."
Mikheil Saakashvili, the Georgian president, called a meeting of the national security council after the attack.
"We are faced with an evil power," he said in televised comments from the council session. "They are very disappointed they could not take Tbilisi and the whole of Georgia. That's why the risks remain high."
The village was the location of a Russian checkpoint during the war with Georgia in August, before Russia pulled back its troops.
Russia entered Georgia in August to support the South Ossetia separatist movement in the north of the country.
South Ossetia and Abkhazia declared independence from Georgia in the early 1990s, however only a few nations, including Russia, recognises their authority.
A French-brokered ceasefire deal saw Russian troops withdraw in October from buffer zones around the two regions.