By 4 September the First and Second armies had slowed the advance of the 7th and 6th armies west of St. Dié and east of Nancy, from where the Second Army had withdrawn its left flank, to face north between Nancy and Toul. A gap between the left of the Second Army and the right of the Third Army at Verdun, which faced north-west, on a line towards Revigny against the 5th Army advance, west of the Meuse between Varennes and St. Ménéhould. The Fourth Army had withdrawn to Sermaize, west to the Marne at Vitry le François and then across the river to Sompons, against the 4th Army, which had advanced from Rethel, to Suippes and the west of Chalons. The new Ninth Army held a line from Mailly against the 3rd Army, which had advanced from Mézières, over the Vesle and the Marne west of Chalons. The 2nd Army had advanced from Marle on the Serre, across the Aisne and the Vesle, between Reims and Fismes to Montmort, north of the junction of the Ninth and Fifth armies at Sezanne. The Fifth Army and the BEF had withdrawn south of the Oise, Serre, Aisne and Ourq, pursued by the 2nd Army on a line from Guise to Laon, Vailly and Dormans and by the 1st Army from Montdidier, towards Compiègne and then south-east towards Montmirail. The new French Sixth Army, linked with the left of the BEF, west of the Marne at Meaux, to Pontiose north of Paris. French garrisons were besieged at Strasbourg, Metz, Thionville, Longwy, Montmédy and Maubeuge. The Belgian army was invested at Antwerp in the National redoubt and at fortress troops continued the defence of the Liège forts.