Attack on Afghan ministry thwarted KABUL, Afghanistan, March 27 (UPI) -- Officials found suicide vests and arrested more than a dozen Afghan soldiers in a suspected plot to attack the government, Afghan and Western officials said. The Afghan Defense Ministry was in virtual lockdown Tuesday after the vests were found and 16 arrests were made Monday and Tuesday, The New York Times reported. A sergeant who was guarding the ministry said two bombers may still be at large, prompting the lockdown. Only senior officers and people they escorted were allowed to enter or exit the ministry. The detainees were suspected of plotting to attack the ministry and blow up buses ferrying government employees to and from their jobs, the officials said. A Western official told the Times a number of people, including Afghan soldiers, were arrested Monday and Tuesday. Afghan broadcast outlets reported 10 people were arrested Tuesday and six were arrested Monday, although the Times said information wasn't clear about whether the suspects were soldiers or civilians. Intelligence officials told the BBC that 11 suicide jackets were seized. The breach was in one of Kabul's most fortified areas, less than a mile from both the presidential palace and the headquarters of the American-led coalition. The apparent involvement of Afghan soldiers in the anti-government plot has heightened fears of renewed violence in Afghanistan's capital, observers told the Times. Afghan security forces were involved in the deaths of three coalition troops Monday in two incidents. Now Afghan security forces appear to be a threat to their own government, the Times said. Officials said the plot to attack the government was uncovered Monday, but details remained sketchy. The Defense Ministry has denied any attempted bombings had occurred and said no soldiers were arrested.