India, Aug. 18 -- US stock futures fell sharply early Tuesday as investors worried about rising tensions in the Middle East, higher Treasury yields and rising oil prices. These factors are putting fresh pressure on Wall Street before the market opens.

Nasdaq futures were hit the hardest. As of 4:30 a.m. ET, Nasdaq futures were down more than 1%, while S&P 500 futures fell 0.5%. Dow futures dropped 0.2% and Russell 2000 futures declined 0.4%, according to Stocktwits.

Middle East tensions are a major reason behind the market drop. A key Iranian official reportedly said the country had moved to a "fully offensive" military posture after Washington ruled out extending the temporary ceasefire between the US and Iran. Investors are worried th...