The pan-European Stoxx 600 index was down 0.5% during mid-afternoon deals after muted trading through most of the session.
Oil and gas stocks traded 0.1% higher, paring gains of 1.1% earlier in the session despite oil prices remaining in positive territory. Saudi Arabia announced voluntary cuts tio its output Sunday, starting in July. OPEC+ on Sunday announced it would make no changes to its planned oil production cuts for the rest of the year.
Travel and leisure stocks led sector losses, down by 1.3%, as airline group Air France KLM fell 3.5%.
The Stoxx 600 closed 1.5% higher last week, pulling back from a two-month low Wednesday after U.S. lawmakers passed a bill to raise the debt ceiling and cap government spending.
Asia-Pacific markets were largely higher on the U.S. debt ceiling news, while U.S. equity futures were little changed.