The last lifelines into besieged towns along the eastern frontline for Ukrainian troops, caught in a web of increasingly lethal and sophisticated drone warfare, rely on a technology millennia old: a fishing net.

Russia launched 331 aerial assets against Ukraine on the night of 27-28 July: 324 drones, four cruise missiles and three Kinzhal air-launched ballistic missiles. Ukrainian air defence forces have shot down 311 of these assets.

Analysts say Russia has recently made only incremental gains in its slow and costly advance against Ukrainian defenses.

Falling debris from downed drones was reported in four locations, the air force said. Russia's Defense Ministry, meanwhile, said its forces downed 11 Ukrainian drones overnight into Monday morning.

Ukraine says it will give defense firms a detailed report of how their weapons tech fares in combat against Russia's troops.

Russia's drone attacks on Ukraine's infrastructure have begun to target military recruitment centers, according to a data analyst group. Armed Conflict Location and Event Data (ACLED) said Russia began to hit enlistment centers in recent weeks in a concerted effort to disrupt Ukraine's mobilization.

Russia has launched overnight attacks on four Ukrainian cities, injuring at least 15 people and targeting energy infrastructure.

THE HAGUE, July 4 (Reuters) - Dutch and German intelligence agencies have gathered evidence of widespread Russian use of banned chemical weapons in Ukraine, including dropping a choking agent from drones to drive soldiers out of trenches so they can be shot, they said on Friday.