European stocks advanced, with the Stoxx Europe 600 Index climbing the most in more than a month, as U.S. and U.K. markets reopened following a public holiday.

The Stoxx 600 increased 1.3 percent to 308.23 at the close of trading, extending its rally this month to 3.9 percent. The gauge has climbed for 12 consecutive months, its longest winning streak since 1997. The equity benchmark has rallied 10 percent so far in 2013, its best start to a year since 1998, as central banks around the world maintained a combination of monetary stimulus and low interest rates.

National benchmark indexes rose in every western-European market except for Greece and Iceland. The U.K.'s FTSE 100 surged 1.6 percent. France's CAC 40 rose 1.4 percent and Germany's DAX advanced 1.2 percent.

AstraZeneca climbed 2.7 percent to 3,521.5 pence. The company agreed to buy the U.S. developer of an experimental treatment for patients with high levels of triglycerides, a contributory factor to heart attacks and strokes. AstraZeneca's cholesterol-lowering drug, Crestor, will face competition from generic treatments in the U.S. from 2016.

Victrex surged 8.4 percent to 1,765 pence. The U.K. maker of heat-resistant plastics for the auto, energy and health-care industries raised its interim dividend by 15 percent to 10.35 pence per share. Revenue climbed 1 percent in the first half to 106.4 million pounds ($160 million) from a year earlier.

Aixtron jumped 7.8 percent to 13.57 euros, its highest price in more than a year. Natixis raised the stock to buy from neutral, citing a rebounding LED industry that the company should benefit from.

Cie. Financiere Richemont SA, the owner of the Cartier brand, added 3 percent to 91.65 francs. Switzerland's watch exports increased 5.7 percent in April from a year earlier, the country's Federal Customs Offices said today.