MOSCOW - Rosneft and Trafigura will hold a joint party on the sidelines of the oil week in Singapore next month in a sign of growing ties between the Kremlin-owned energy champion and the Swiss trading house. The party will be held on Sept. 8 on the sidelines of the annual Asia-Pacific Petroleum Conference, said an invitation sent to markets participants and seen by Reuters. Rosneft declined to comment. Trafigura confirmed it was holding a joint party with Rosneft without elaborating. Trafigura emerged this year as one of the biggest buyers of Russian oil, expanding its deal with sanctions-hit Rosneft to export crude from Baltic, Mediterranean and Pacific ports. Trafigura is currently lifting some 15 cargoes or 1.5 million tonnes of crude from Rosneft per month, including Urals, CPC Blend and ESPO Blend grades. Before February, Trafigura had been trading only modest volumes of oil with Rosneft under a two-year-old deal usually amounting to no more than two tankers a month. Last year, Rosneft was hit by international sanctions, which limited its access to global financial markets, as part of punitive measures by the West against Moscow for its role in the Ukraine crisis. The squeeze on Rosneft has been compounded by a collapse in oil prices. The sanctions also blocked its ambitions to expand into global oil trading by killing off a deal to buy U.S. bank Morgan Stanley’s oil trading division at the end of 2014. The sanctions forced Rosneft to seek alternative ways to meet debt repayments and maintain liquidity. In February, market sources said Trafigura helped Rosneft to raise short-term financing, which is not forbidden by sanctions. Trafigura has been expanding actively in Russia since beefing up its offices two years ago with traders from the BP’s Russian venture, TNK-BP, led by Jonathan Kollek. This year’s deal allowed Trafigura to catch up with rivals Glencore and Vitol, which had previously dominated Russian oil trade.