In the meantime, Bonaparte marched with the Army of the Reserve, not to the relief of Genoa, but to Milan where he spent six days. By the end of May, plague had spread throughout Genoa and the civilian population was in revolt. Negotiations were begun for the exchange of prisoners early in June, but the citizens and some of the garrison clamoured for capitulation. Unknown to Masséna, the Austrian general Peter Ott, had been ordered to raise the siege because Bonaparte had crossed Great St. Bernard Pass and was now threatening the main Austrian army. Describing the situation at Genoa, Ott requested and received permission to continue the siege. On 4 June, Masséna's negotiator finally agreed to evacuate the French army from Genoa. However, if the word capitulation was mentioned or written, Masséna threatened to end all negotiations.