Georgia was probing on Wednesday the attempted murder of an opposition lawmaker whose car exploded in central Tbilisi just days before parliamentary polls. Givi Targamadze, who is running for office for the ex-Soviet republic's main opposition United National Movement (UNM) party, told journalists that an explosive device planted in the back of his car detonated on Tuesday night. Targamadze, who was sitting in the front of the vehicle, was unhurt. Four passers-by were rushed to hospital, one of them with "serious but not life-threatening injuries," Health Minister David Sergeyenko said in televised comments. Prime Minister Giorgi Kvirikashvili condemned the incident Wednesday as "sabotage against the state" committed by the country's "enemies" who "will be held accountable to the fullest extent of the law." Police launched an investigation on Tuesday night into what deputy interior minister Besik Amiranashvili called "attempted murder in aggravating circumstances." UNM leader David Bakradze said that "no matter who was behind the car attack, the authorities are responsible for creating a climate of hatred in which opposition politicians are being attacked." Targamadze was featured in a 2012 Russian television film which alleged he and a group of Kremlin critics plotted attacks in Russia. The film led to a court case that saw several Russian opposition members jailed. Targamadze himself is wanted in Russia. Georgia will hold parliamentary elections on Saturday that will see the UNM and the ruling Georgian Dream party clash in a bitter power struggle. The two pro-Western parties are neck and neck in opinion polls and have equal chances of forming Georgia's next government. The car bomb attack was not the first violent incident to occur in the lead-up to the vote. On Sunday, unknown assailants fired shots during a campaign rally of MP candidate Irakli Okruashvili in the central city of Gori, injuring two men. The UNM, which was founded by former president Mikheil Saakashvili, has accused the Georgian Dream government of orchestrating a political witch-hunt. Several of Saakashvili's top allies have been probed and some jailed since the Georgian Dream party defeated UNM in parliamentary and presidential elections in 2012 and 2013. Western countries voiced concerns over what they perceive as a pattern of persecution of political opponents. Saakashvili is wanted by Georgian prosecutors for alleged abuse of office during his nine-year rule — charges he denounces as politically motivated.