BISSAU (AFP) - Guinea-Bissau's army denied staging a coup Monday after soldiers assassinated veteran President Joao Bernardo Vieira in apparent reprisal for a bomb blast which killed the head of the military. The army pledged to respect "constitutional order" and called on the population to stay calm in the wake of the killings, which were roundly condemned by the international community. Soldiers gunned Vieira down as he fled his home in the early hours of Monday following turmoil in which the army chief was killed in a bomb explosion hours before, military officials said. The West African nation's army blamed Vieira, 69, for the death of its leader, General Tagme Na Waie, military spokesman Zamora Induta told AFP. Vieira's supporters and the army fought in the capital, Bissau, on Sunday and rocket explosions and automatic weapon fire could still be heard in the capital in the early hours of Monday. The naval commander said the army had given the prime minister guarantees that it would remain faithful to democratic principles. The army said earlier the situation in the country was "under control" but warned that it would not tolerate "looters and troublemakers." Meanwhile, the cabinet announced seven days of national mourning and directed the public prosecutor's office to launch an inquiry into both deaths. EU foreign policy chief Javier Solana also condemned Vieira's killing, as did the United States and former colonial power Portugal, whose Prime Minister Jose Socrates offered his nation's help "to keep constitutional order." Nevertheless, the White House said it would be keeping a close watch on developments, a senior Obama administration official, adding: "We want there to be stability defined by respect of the rule of law." UN chief Ban Ki-moon Monday slammed the assassination of Guinea-Bissau president Joao Bernardo Vieira and called for calm in the West African nation amid international concern at the violence.