SINGAPORE: Oil prices were mixed in cautious Asian trade on Friday after the Federal Reserve kept its benchmark interest rate at zero but warned about weaknesses in the global economy. News that the US central bank would keep borrowing costs at zero was broadly welcomed across Asia, with most stock markets up, as it eased concerns about a feared flight of capital from the region’s struggling economies. It also weakened the greenback, making dollar-priced oil less expensive for traders with weaker currencies. However, Fed Chief Janet Yellen said in a news conference that bank policymakers cited the ongoing crisis in China and recent turmoil on world markets as playing a role in the decision.