July 23 (Reuters) - European shares edged lower on Thursday, weighed down by weakness in technology stocks following quarterly results from U.S. giant Alphabet, as markets monitored developments in the Middle East conflict ahead of the European Central Bank's monetary policy meeting.

The pan-European STOXX 600 index fell 0.5 percent to 643.47 points by 0705 GMT.

Shares of technology companies fell 2.7 percent on Thursday, with STMicroelectronics leading the decliners as its stock plunged 15 percent after the chipmaker predicted that its average third-quarter revenue would be slightly below market expectations.

Shares of BE Semiconductors fell 4.6 percent after the company announced its second-quarter results.

Alphabet on Wednesday increased its 2026 capital spending plans by $15 billion, raising doubts about whether its artificial intelligence investments will pay off.

The STOXX energy sub-index rose 0.6 percent as Brent crude futures climbed above $96 a barrel after the United States launched a new round of strikes on Iran and Houthi rebels in Yemen targeted oil tankers in the Red Sea, widening the scope of a conflict that has upended global interest rate expectations.

All eyes are on the European Central Bank's monetary policy decision on Thursday, with it widely expected to leave interest rates unchanged.