non-military purposes, and some of these flights were authorized by the UN. Under the operation's rules of engagement, NATO fighters were only authorized to shoot down helicopters that committed a hostile act. Otherwise, NATO fighters issued orders to "land or exit", in other words, land the aircraft or leave the no-fly zone. Typically, helicopters in Bosnian airspace complied with these orders by landing, but then took off again after NATO forces departed. None of the parties in the conflict respected the ban on helicopter flights, as evidenced when Ratko Mladić responded to a BBC journalist's question about his violation of the ban with the statement, "The commander of the Bosnian Serb armed forces does not ride on a donkey." Deceptive markings on helicopters further complicated matters for NATO pilots. Many of the combatants painted their helicopters to look like those of organizations that the UN's Zagreb Flight Coordination Center had authorized to fly in restricted space. For example, the army of the Republika Srpska often painted a Red Cross logo on their helicopters, and Croatian helicopters were given markings similar to those of UN humanitarian aid helicopters. The questionable identity of these helicopters became particularly problematic after the Black Hawk Incident in Iraq, because NATO pilots became more reluctant to engage potential belligerents without clear identification. As a result of the rules of engagement and difficulties in aircraft identification, NATO forces proved unable to stop most unauthorized helicopter flights, resulting in a documented total of 5711 unauthorized flights during the conflict. Close air support and air strikes Even before Operation Deny Flight began, a number of US officials lobbied for a large role for NATO air power in Bosnia. In particular, as part of Bill Clinton's platform during his 1992 campaign for President of the United States he promised a "lift and strike" policy, which included the use of air strikes against Bosnian Serb forces. After the commencement of Operation Deny Flight, US officials, including President Clinton, pushed for an expanded mission. After the Bosnian Serbs rejected the Vance-Owen Plan on 6 May 1993, Clinton and other US officials intensified these calls and they discussed the possibility of using large-scale strikes to coerce the Serbs into acceptance. Ultimately, no such strikes were approved or carried out, but American officials became more open to the idea of using air power for coercion. In June 1993, partly in response to pressure from