MOSCOW (Reuters) -Russian forces on Monday claimed full control of the vast Soviet-era coke plant in the ruined Ukrainian town of Avdiivka , cementing the biggest battlefield gain in nine months after one of the most intense battles of the war. The fall of Avdiivka is Russia's biggest gain since it captured the city of Bakhmut in May 2023, and comes almost two years to the day since President Vladimir Putin triggered a full-scale war by ordering the invasion of Ukraine. Russia's defence ministry said its troops had advanced about 9 km (5 miles) in that part of the 1,000-km (620-mile) front line, and that Russian troops were pressing forward after an deadly urban battle.