At least five people have been killed and some 100 others injured after a metro train derailed in Moscow during Tuesday morning’s rush-hour.<br /><br />It happened between two stations in the west of the city.<br /><br />The train braked suddenly, according to witnesses, reportedly after a technical problem on the line.<br /><br />At least seven people were said to be trapped inside one of the derailed carriages, with thick smoke reported inside. Some 200 people were evacuated from the disaster zone.<br /><br />Dozens of ambulances and a helicopter were called in. Moscow’s mayor Sergueï Sobianine also rushed to the scene between the Slaviansky Boulevard and the Park Pobedy stations.<br /><br />At least half of those hurt are said to be in a serious condition.<br /><br />One of the world’s oldest underground systems, the Moscow metro is also one of the biggest.