On 27 August 1916 Colonel Zymbrakakis, a local hero of the Balkan Wars, established a "Committee of Public Safety" in Salonika with Sarrail's open support, and pledged to establish a "National Army" which would fight the Bulgars harder than the Royalist officers who had surrendered their positions in May. Some Royalist Greek forces defected, whilst others were coerced by Venizelist Greeks into changing sides. In September, an Allied naval force arrived off Piraeus, but King Constantine rejected its most important terms. On 10 September an Allied counteroffensive began. On 12 September Serb troops, supported by French artillery, attacked Mount Kajmakcalan, capturing and holding it over a fortnight of fighting. Two French divisions and a Russian brigade attacked towards Kenail and the British up from the Struma Valley, at each point meeting trenches dug under German supervision. By 17 September "Zouaves" and the French Foreign Legion occupied Florina.