On the last day of April, 1916, however, the army of Archduke Joseph Ferdinand started a new strong offensive movement north of Mouravitzy on the Ikva in Volhynia. Heavy and light artillery prepared the way for an attack in considerable force against Russian trenches which formed a salient at that point, west of the villages of Little and Great Boyarka. The Russians had to give ground, but soon afterward started a strong counterattack, supported by heavy artillery fire, and regained the lost ground, capturing some 600 officers and men. In the southern half of the eastern front, just as in the northern half, there was little change in the character of fighting with the coming of May and the improvement in the weather. Artillery duels, aeroplane attacks, scouting expeditions, and local infantry attacks of limited extent and strength were daily occurrences. On May 1, 1916, Austro-Hungarian detachments were forced to withdraw from their advanced positions to the north of the village of Mlynow. This place is located on the Ikva River, some ten miles northwest of the fortress of Dubno. Here the Russians had made a slight gain on April 28, 1916, and when they made an attack with superior forces from their newly fortified positions, they were able to drive back the Austro-Hungarians still a little bit farther. Twenty miles farther north, in the vicinity of Olyka, the little town about halfway between the fortress of Lutsk and Rovno, on the railway line connecting these two points, the Russian forces reported slight progress on May 2, 1916. Northwest of Kremenets, in the Ikva section, Austro-Hungarian engineers succeeded in exploding mines in front of the Russian trenches. But the Russians themselves promptly utilized this accomplishment by rushing out of their trenches and making an advanced trench of their own out of the mine craters dug for them by their enemies. Two days later, on May 4, 1916, the Russians were able to improve still more their new positions southeast of Olyka station, and to gain some more ground there. Repeated Austro-Hungarian counterattacks were repulsed. The same fate was suffered by determined infantry attacks on the Russian trenches in the region of the Tarnopol-Pezerna railway, in spite of the fact that these attacks were made in considerable force and were supported by strong artillery and rifle fire. Later the same day an engagement between reconnoitering detachments in the same region, southwest of Tarnopol, resulted in the capture of one Russian officer and 100 men by their Austro-Hungarian opponents.