Russian forces have failed to make any major gains over the last 24 hours in their offensive in Ukraine as counterattacks by the defenders have hampered their efforts, according to UK intelligence and U.S. analysts.British intelligence said in an April 23 operational update that Ukraine’s airspace and its Black Sea waters remain contested as Russian air and maritime forces have been unable to establish control in either domain “owing to the effectiveness of Ukraine’s air and sea defense.”“Despite increased activity, Russian forces have made no major gains in the last 24 hours as Ukrainian counterattacks continue to hinder their efforts,”...