Only a few Polish units managed to break out of the encirclement. These groups entered Warsaw and Modlin, mostly around 19 and 20 September, crossing the Kampinos Forest, and fighting German units in the area (for example, in the battle of Wólka Węglowa). Among them were Generals Kutrzeba, Knoll-Kowacki and Tokarzewski, two cavalry brigades (Wielkopolska and Podolska) of General Abraham, and the 15th and 25th Infantry Divisions. The remainder (4th, 14th, 17th, 26th and 27th Infantry Divisions), which didn't manage to cross the river, with General Bortnowski, capitulated between 18 and 22 September. Polish casualties were estimated at 20,000 dead, including three generals: Franciszek Wład, Stanisław Grzmot-Skotnicki and Mikołaj Bołtuć. German casualties are estimated at 8,000 dead.