European stocks fell, after posting a weekly gain, as the U.S. and Europe threatened tougher sanctions on Russia over its suspected role in the shooting down of flight MH17 in Ukrainian airspace.

"The conflict in Gaza, the Ukraine crisis -- these are the main topics," Soeren Steinert, who helps manage about $24 billion as associate director for equities trading at Quoniam Asset Management GmbH in Frankfurt, said in a phone interview. "I can't see any panic selling. It is only just that people are not willing to buy. There is no conviction that the market should be falling further."

National benchmark indexes fell in 14 of 18 western European markets. The U.K.'s FTSE 100 slipped 0.3 percent. France's CAC 40 lost 0.7 percent. Germany's DAX declined 1.1 percent to the lowest level since May 9.

In the Middle East, diplomatic efforts to end two weeks of Gaza Strip fighting intensified after battles killed dozens of Palestinians and 13 Israeli soldiers in the conflict's bloodiest single day.

Commerzbank fell 1.9 percent to 10.74 euros. Germany's markets regulator BaFin found high operational risks and problems in the lender's internal accounting system in 2013, Capital magazine reported, citing an unreleased BaFin report. The review didn't find any errors in Commerzbank's reporting, the magazine said.

Julius Baer jumped 8.3 percent to 39.60 Swiss francs. The wealth manager founded in 1890 said first-half net income climbed to 178.3 million francs ($198 million) from 114 million francs a year earlier. Assets under management rose by 20 billion francs to 274 billion francs.

Tesco Plc added 1.3 percent to 288.65 pence after saying Unilever's Dave Lewis will replace Philip Clarke as chief executive officer on Oct. 1. The retailer also said first-half sales and trading profit are below expectations.

Sky Deutschland AG climbed 4.5 percent to 6.70 euros, the biggest gain since May 12. Rupert Murdoch's 21st Century Fox Inc. may reach an agreement to sell its 57 percent stake in the company to British Sky Broadcasting Group Plc in the next two weeks, two people familiar with the matter said. The Sunday Times reported yesterday that BSkyB is close to a deal to buy the European assets from Fox. BSkyB fell 1.5 percent to 904 pence today.