[NEW YORK] US stocks opened lower on Thursday as the Yemen crisis lifted oil prices amid worries US equities have become overvalued.
Five minutes into trade, the Dow Jones Industrial Average stood at 17,628.88, down 89.66 points (0.51 per cent).
The broad-based S&P 500 fell 9.28 (0.45 per cent) to 2,051.77, while the tech-rich Nasdaq Composite Index lost 43.93 (0.90 per cent) at 4,832.59.
Saudi warplanes bombed Huthi rebels in Yemen on Thursday, launching an Arab military intervention in support of Yemen's embattled president that regional rival Iran warned was a "dangerous" move.
US oil prices rose above US$50 a barrel as Kuwait beefed up security at oil facilities.
Analysts have pointed to growing concerns that US stocks are overvalued, particularly in biotechs, semiconductors and some other sectors. The upcoming first-quarter earnings season is expected to be weak.