The remaining threat from Polish forces generated calls for attacks on Warsaw. Air attacks against the city had been planned for the first day, codenamed "Wasserkante", or Operation Seaside. Just after midnight on 12/13 September, the Luftwaffe chief of staff Hans Jeschonnek ordered Löhr to prepare to attack ghettos in northern Warsaw, in retaliation for unspecified war crimes against German soldiers in recent battles. Richthofen's airmen flew 183 to 197 sorties, dropping equal quantities of high explosives and incendiaries. Some bombs fell close to German forces conducting the Siege of Warsaw and smoke made it impossible to assess damage. Richthofen confronted Hermann Göring over the need for a united air command for the Warsaw campaign and hinted he was the man for the job. He did not get his way until 21 September. Weather delayed the attack, which began on 22 September. That morning von Richthofen signaled the OKL; "Urgently request exploitation of last opportunity for large experiment as devastation and terror raid", and added "every effort will be made to completely eradicate Warsaw." The OKL rejected the proposal. Leaflets demanding the city's surrender had been dropped on four days earlier, but Richthofen began acting on his own initiative, using Luftwaffe Directive 18, dated 21 September, which gave him responsibility for the conduct of air operations.