European stocks declined for a second day, extending a one-month low, amid speculation the Federal Reserve will cut back its debt-buying program and as a gauge of Chinese manufacturing fell. Asian shares dropped while U.S. index futures were little changed.

The Stoxx Europe 600 Index slid 0.6 percent to 299.08 at 10:28 a.m. in London, the lowest level since

The Stoxx 600 has still fallen 3.8 percent since May 22 as investors weighed the likelihood of the Fed taking steps to reduce monetary stimulus. Fed Bank of San Francisco President John Williams, who has emphasized the need for policy flexibility, will speak at conference held by the Swedish Riksbank at 1:20 p.m. in Stockholm.

HSBC Holdings Plc and Markit Economics said their Chinese manufacturing index, released today, fell to 49.2 in May from 50.4 in April. A reading below 50 signals contraction. An official index for the world's second-biggest economy, released June 1, rose to 50.8 last month from 50.6 in April. In the U.S., the Institute for Supply Management's factory index held at 50.7 during the month, according to the median forecast of economists.

Roche, the world's biggest maker of cancer drugs, fell 1.4 percent to 235.70 Swiss francs for the longest losing strak since November 2011. Avastin failed to extend the survival of patients with deadly brain tumors in a study that found no advantage in using the drug as a first-line therapy against the cancer known as glioblastoma.

Sanofi (SAN) lost 1.6 percent to 81.21 euros. The Paris-based drugmaker will take a $285 million impairment as iniparib failed to help patients with lung cancer. It will also halt development of an anti-coagulant, otamixaban, after the drug showed no benefit over existing therapies in a study.

Renault SA led French carmakers lower, falling 1.6 percent to 58.81 euros. Registrations of cars and light vehicles for Renault fell 17 percent in May, according to the French carmakers association. PSA Peugeot Citroen's registrations dropped 8.2 percent. Peugeot declined 1 percent to 6.76 euros.

FTSE 100 6,556.27 -26.82 -0.41%

CAC 40 3,925.45 -23.14 -0.59%

DAX 8,285.27 -63.57 -0.76%