 The army, strengthened by German mercenary forces, was harassed by the rebels, and, in turn, plundered and massacred Lysianka, Dymer and several other Ukrainian settlements, then crossed the Dnieper where they were met by the rebels, both front and rear, as more Ukrainians rose in what became an area-wide rebellion against the Poles.The indecisive skirmishes around Pereiaslav lasted three weeks until the .Koniecpolski laid siege to the Cossack stronghold, but lacking the support of artillery and infantry, he could not break its walls; the Cossacks, however, were lacking supplies and agreed to negotiations.