European stock markets fell as escalating Middle East tensions made investors cautious, while disappointing earnings from Hermes International SA and ASM International further hurt market sentiment.

The Stoxx Europe 600 index closed 0.3% lower in London. It initially opened higher, but turned negative after U.S. President Donald Trump stated he would strike Iran "very hard" in response to an attack on a U.S. military base in Jordan. Brent crude oil rose 7% to around $90 per barrel.

Hermes International SA was one of the biggest drags on the index, with its shares plunging 11%. The Birkin bag maker warned of a weakening market. Chip equipment manufacturer ASM International fell 4.8% as its outlook was deemed insufficiently optimistic by the market.

"There is a very large divergence in performance within each sector. This is a true stock-picker's market, where individual stock movements are primarily driven by company-specific factors," said Amélie Derambure, a senior multi-asset portfolio manager at Amundi.