MOSCOW/VIENNA (Reuters/AFP) Russia and the United States conducted the biggest spy swap since the Cold War on Friday, trading agents on Vienna airport tarmac in an evocative climax to an espionage drama that had threatened improving ties. Two aircraft - one Russian, one American - parked side by side for around 90 minutes as vehicles shuttled between them. The agents changed places under the cover of gangways as waves of heat rose from the blistering blacktop. The Russian plane then took off, followed by the US jet in an echo of Soviet-era spy trades across the Iron Curtain in central Europe. Officials in Vienna, once a centre of Cold War cloak-and-dagger intrigue, maintained a strict news blackout. The US and Russia have completed a spy swap in Vienna, the US Justice Department said in a statement Friday, confirming Moscow had released four people in exchange for 10 Russian agents. The US has successfully transferred ten Russian agents to the Russian Federation and the Russian Federation has released four individuals who had been incarcerated in Russia, the department said. The American plane made a brief stop at the Brize Norton airbase in central England before taking off again, British media reported. The jet landed at Domodedovo airport outside Moscow a few hours later. Shielded from cameras, the Russians stepped off the plane and were whisked away in a convoy of SUVs, sedans and small buses. The dramatic conclusion to the espionage scandal which has gripped America came after spymasters brokered the deal on the instructions of presidents keen not to derail important diplomatic breakthroughs in Russian-US relations. In the first step of the carefully choreographed swap, the 10 Russian agents pleaded guilty on Thursday in a New York court to charges against them and were immediately deported. Russias Foreign Ministry said in a statement that the spy swap gives reason to expect that the course agreed on by the leaders of Russia and the US will be consistently implemented in practice and that attempts to knock the parties off this course will not succeed. But the exchange - which one Russian internet site quipped was Russia 10: USA 4 - may add fuel to Republican accusations that Obama is being too soft on Moscow. A key 11th suspect named by US authorities disappeared after being granted bail following his arrest in Cyprus. Russias Foreign Intelligence Service declined all comment on details of the affair. Spymasters on both sides say that despite generally warmer relations, the two former Cold War foes still fund generous intelligence operations against each other. The scandal broke when the US said on June 28 it had uncovered a ring of suspected Russian secret agents who were using false identities to try to gather sensitive intelligence on the United States. Igor Sutyagin, one of the four Russians sent westward on Friday, was sentenced to 15 years in prison in 2004 for passing information to a British firm prosecutors said was a CIA front, but supporters saw him as a political prisoner. Sutyagin said the information was available from open sources, and Kremlin critics said his conviction - which cast a chill on Russian scientists - was part of a crackdown on scholars with Western ties under Putin, president at the time.