Singapore shares opened nearly flat with a positive bias on Thursday, taking cues from the choppy movement in the U.S. markets that closed lower on Wednesday.

The Straits Times Index (STI), a key benchmark for the Singapore Exchange, rose marginally in early trade by 0.4%, or 18.71 points, to open at 5,180.21.

Investors are taking cautious calls and watching out for cues on interest rates and developments in the Middle East.

U.S. Federal Reserve Chairman Kevin Warsh on Wednesday said the risks of higher inflation have receded; however, he did not comment on whether the central bank needed to consider a rate increase later this month.

Investors are also closely eyeing the development in Iran as Qatar says "positive progress" has been made in US-Iran negotiations during the first indirect talks.