Early in 1916 Sarrail ordered his forces up 70 km from Salonika to form a larger perimeter from the Vardar to the Gulf of Strymon. In May 1916 he extended his line west to Florina. The refitted Serb divisions were transported into Salonika, escorted by a French naval squadron which had based itself at Argostoli, again to the fury of the Greek government. 122,000 Serbs arrived in May. In May Greek forces surrendered the fortress of Rupel on the Struma without a fight, and in early June Sarrail used alleged collaboration between the commandant of a Greek frontier fortress and the Bulgars as an excuse to proclaim a state of siege in Salonika and Allied jurisdiction over the area occupied by his troops. The French took control of rail, postal and telegraph services, whilst Sarrail sent a naval squadron to threaten Athens. Briand supported this, but British suspicions were further raised, particularly by local French entrepreneurial activity and the opening of French schools. Under Allied political pressure King Constantine dismissed Prime Minister Skouloudis on 22 June, but refused to disarm the Greek troops at Salonika. By mid-July the Serb divisions had moved into position on the left of Sarrail's front, with the British, whose government were still lukewarm, on the right. On 23 July Sarrail was placed in command of all Allied forces at Salonika, although they retained right of appeal to their governments. A brigade of Russians arrived in late July. By early August there were 382,728 Allied soldiers at Salonika, and an Italian division arrived in the second week of August, bringing the total up to 400,000 men. Given the effects of malaria and the need to detach troops to build and guard transport links, he lacked reserves. His British forces lacked artillery, although he was given 40 French aircraft and some French passenger liners to use as hospital ships.