Seven Venezuelan military officers were killed on Saturday when their helicopter crashed outside Caracas, President Nicolas Maduro said. The helicopter had left the Venezuelan capital heading to San Carlos in the country's northwest when it went down in a mountainous area of the El Hatillo municipality, the defence ministry said in a statement. On Twitter, Maduro mourned the loss of "seven worthy officers of the country", including two majors, three captains and two lieutenant colonels. The defence ministry said an investigation into the cause of the crash was under way. Maduro was in San Carlos on Saturday, leading military exercises with top brass and more than 5,000 troops. It was a show of strength against opposition leader Juan Guaido, whose attempt to launch a military uprising earlier in the week had failed.