Kommersant reported that Russia is having difficulty delivering 11 Su-35s to Indonesia due to the U.S. Law on Countering the Opponents of the United States through Sanctions (CAATSA).
By Eugeny Polivanov (http://russianplanes.net/id169356) [CC BY-SA 4.0 or CC BY-SA 4.0 ], via Wikimedia Commons
Earlier, it was reported that Indonesia will take delivery of the first aircraft this month. However, this is not possible now because of potential sanctions.
Financial aspects of the deal is also under threat as the U.S. could sanction one of the commercial bank that is providing loan to Indonesia to finance the deal.