Russian warplanes took off one after another with roaring thunder on Wednesday from their base on Syria ' s coast, which bustled with activity as Moscow pressed its air blitz days before scheduled peace talks. Helicopter gunships swept low around the base in the province of Latakia to prevent any possible attack. Even though the front line is dozens of kilometers away and the area around the base is tightly controlled, the Russian military methodically patrols the area to make sure there is no ground threat. Two heavy transport planes were parked near the main terminal as soldiers toting assault rifles stood guard. Since Russia launched its air campaign in Syria on Sept. 30, its warplanes have flown 5,700 missions. The number is remarkable for a compact force comprising just a few dozen warplanes. The Russian military brought a group of Moscow-based reporters to the base on Wednesday to see the operations. Defense Ministry spokesman Maj. Gen. Igor Konashenkov said that by afternoon Russian warplanes had flown about 40 sorties, with each aircraft hitting from three to five targets on a single run. In the early stages of the campaign, planes struck only one target during each mission. In the time since The Associated Press first visited the Hemeimeem base in October, the military has put a second runway into service and has deployed powerful air defense weapons. The towering launch tubes and massive radar arrays of the long-range S-400 missiles could be seen at the edge of the base. Asked how long the Russian air campaign may last, Konashenkov said only that Russia's goal is to strike extremist infrastructure in support of Syrian government troops. "They have shown some good results in defeating terrorist groups," he said. The Russian military has insisted it is targeting the Islamic State group and other extremists and has angrily dismissed Western accusations of hitting moderate rebels fighting Syrian President Bashar Assad. Moscow also has rejected claims that its aircraft have hit civilians, insisting all casualties have been at extremist facilities away from populated areas. Konashenko said Syrian government forces backed by Russian airstrikes have retaken about 250 villages and towns from extremists. Each target is verified through multiple intelligence sources, and every fifth target Russia hits is now chosen thanks to information from "patriotic" opposition forces, he said. Konashenko said one particularly successful strike was conducted Tuesday in the Aleppo province, where a Russian Su-34 bomber hit a meeting of extremist leaders. Russian ordnance includes bunker-buster bombs capable of piercing seven meters (23 feet) of rock to destroy underground facilities, Konashenko said. Some of the bombs are laser-guided, but all Russian warplanes at the base are equipped with a sophisticated targeting system, allowing them to use even regular bombs with pinpoint accuracy, he said. British Defense Minister Michael Fallon on Wednesday once again raised Western concerns about civilian deaths as a result of the Russian air strikes. "I am very concerned at the number of civilian casualties through the use of unguided munitions; seems to be several hundred casualties now," he said in Paris during a meeting of Western defense ministers on how to combat the Islamic State group. "We've seen Russian strikes on opposition forces, on towns and villages, particularly in the south of Syria, which is simply prolonging the Syrian war, propping up Assad and is actually delaying the day on which we can all unite and properly get Daesh out of Syria."