European stocks opened the week on a cautious note, with the STOXX 50 trading little changed while the STOXX 600 slipped 0.2%.
Investors returned from the weekend to renewed upward pressure on oil prices as the conflict in the Middle East continued to escalate.
The US launched a ninth consecutive day of strikes against Iran, while Iran responded with attacks on targets across the region.
Meanwhile, shipping activity through the Strait of Hormuz remained severely constrained.
Markets are also preparing for a busy week of corporate earnings.
Ryanair shares fell around 3% after the airline reported a 34% decline in profit.