Shakhtar Donetsk players ran out on to the pitch between air raid sirens for their final training session on Monday before Ukraine begins a new season of their national league. As Ukrainian soldiers battle Russian forces in the east and south, Shakhtar are due to play Metalist 1925 from the eastern city of Kharkiv in the opening game of Ukraine's Premier League on Tuesday. The match in Kyiv kicks off a day before Ukraine marks six months since Russia invaded its smaller neighbour and is still raging on. "This will be a unique competition: It will happen during a war, during military aggression, during bombardments," Andriy Pavelko, head of the Ukrainian Association of Football, told <i>Reuters</i> in an interview. Matches will be played without fans in the stands due to the risk of bombs and missiles. Two top-flight clubs - Desna Chernihiv and FC Mariupol - are being replaced in the 16-team league after their stadiums were destroyed in fighting. FC Mariupol's whole future has been thrown into question after Russia captured the club's home city in a three-month siege. Pavelko said much of the impetus to restart the football season in the fraught circumstances had come from President Volodymyr Zelenskiy and the Ukrainian army, who hope the league will help lift national morale. "Many people at the front lines asked us to start thinking about restarting football in our country," Pavelko said. He toured Ukraine in March and April to convince club presidents not to let their teams wither away, and to prepare them for a new season, he said. Shakhtar, one of the favourites for this year's title who will also compete in Europe's Champions League, are no strangers to war: they had to relocate from their home city of Donetsk in 2014 when the city was captured by Russia-backed separatists. The forced relocation didn't stop Shakhtar's on-pitch success: they have won five titles in eight seasons since then. They were leading the table on February 24, when the season came to an abrupt halt as Russia invaded and missiles rained down. For years, Shakhtar, owned by Ukraine's richest man Rinat Akhmetov, relied on superstars from Brazil, where the club built a large scouting network, to make the core of their team. After an exodus of foreign players caused by the war, Croatian head coach Igor Jovicevic, who was appointed in June, is now trying to rebuild the squad with young, home-grown players. "For a long time, there was a Brazilian Shakhtar, a top team," Jovicevic said on the sidelines of Shakhtar's training session on Monday. "But now we have to forget about this, and prepare the new [team] as quickly as possible," he said. The new season presents an array of logistical challenges, including the risk of missile strikes. All stadiums must have bomb shelters. To start with, matches will only be played in Kyiv, its surrounding region and two western provinces near the border, though that may change later, Pavelko said. Every time an air raid siren sounds, a daily occurrence in most regions, the game will be stopped for players and match officials to take shelter in basements until the all-clear, Pavelko said. That has left some players like Shakhtar's stalwart midfielder Taras Stepanenko worried about how they will keep their muscles warm in games that are broken up with long breaks. "It will be hard if it lasts more than an hour. Maybe they should set up some [training] bicycles for us," Stepanenko said. Military officials will be present at every game and if an air raid siren lasts more than an hour, they will confer with the referee to decide whether to wait or to postpone the match completely, Pavelko said. Pavelko said the war has not only destroyed facilities, but has also scuppered the futures of thousands of young talented players. "This isn't just about losing stadiums. This is about a whole generation of footballers who won't be able to develop."