Sept 29 (Reuters) - Eastbound gas flows to Poland from Germany and to Europe via Ukraine were steady on Thursday, while a fourth leak was detected on the Nord Stream pipeline system.
Exit flows through the Yamal-Europe pipeline at the Mallnow metering point on the German border stood at 5,764,741 kilowatt-hours per hour (kWh/h) between 0800 and 0900 CET, unchanged from their level at midnight and in line with nominations, or requests for gas.
Russia's Gazprom said it would ship 42.5 million cubic metres (mcm) of gas to Europe via Ukraine on Thursday versus the 41.6 mcm it said it would ship on Wednesday.
There are concerns that if Russia introduces sanctions against Ukraine's Naftogaz over an arbitration case row, that could prohibit Gazprom from paying Ukraine transit fees, which analysts said could end Russian gas flows to Europe via the country.
Nominations for Russian gas into Slovakia from Ukraine via the Velke Kapusany border point stood at 36.9 mcm, up slightly from the previous day, Ukrainian transmission system data showed.
Gas flows via the Nord Stream 1 pipeline, which crosses the Baltic Sea from Russia to Germany, remained at zero.
The pipeline was shut on Aug. 31 for what was supposed to be three days of maintenance, but has not reopened, with Moscow blaming supply disruptions on Western sanctions and technical issues.
Sweden's coast guard discovered a fourth gas leak on the damaged Nord Stream pipelines earlier this week, a spokesperson told the Svenska Dagbladet newspaper.
The European Union suspects sabotage was behind the gas leaks on the subsea Russian pipelines to Europe and has promised a "robust" response to any intentional disruption of its energy infrastructure. (Reporting by Nina Chestney; editing by Jason Neely)