European stocks surged the most in six months after the European Central Bank held its benchmark interest rate at a record low and said it’s ready to act if necessary as the growth outlook dims.

ECB President Mario Draghi said officials are ready to add more stimulus to the euro region’s economy if necessary, while damping expectations that another round of three-year funding for banks is imminent.

National benchmark indexes climbed in all 17 western European markets that were open. Germany’s DAX rose 2.1 percent, while the U.K.’s FTSE 100 gained 2.4 percent in its first day of trading this week after a two-day holiday for the royal jubilee. France’s CAC 40 also rallied 2.4 percent.

A measure of mining companies climbed the most of the industry groups on the Stoxx 600 after copper rose in London. Copper miners Kazakhmys Plc and Vedanta Resources Plc advanced 7.4 percent to 714.5 pence, and 9.1 percent to 963.5 pence, respectively.

Lloyds Banking Group Plc rose 5.2 percent to 27.05 pence after agreeing to sell 809 million pounds of Australian corporate real estate loans to a Morgan Stanley and Blackstone Group LP joint venture for about 388 million pounds in cash.

Royal Ahold NV paced declining shares, falling 4.2 percent to 9.18 euros after the owner of Stop & Shop grocery stores reported first-quarter earnings that missed estimates.

U.S. stocks rallied, giving benchmark indexes their biggest gains in 2012, on speculation global policy makers will take steps to stimulate economic growth.

Equities rallied today as European Central Bank President Mario Draghi said officials stand ready to act as the euro region’s outlook worsens. Federal Reserve Bank of Atlanta PresidentDennis Lockhart said extending Operation Twist, the program to lengthen maturities of debt on the U.S. central bank’s balance sheet, is an “option on the table.”

The U.S. economy maintained a moderate pace of growth, according to the Fed’s Beige Book survey of business conditions. The policy-setting Federal Open Market Committee meets June 19-20 to consider whether more stimulus is needed.

All 10 groups in the S&P 500 rose today as energy, financial and industrial shares had the biggest gains. Bank of America (ВАС) increased 7.6 percent, the most in the Dow, to $7.64. Caterpillar (САТ), the largest maker of construction equipment, added 3.6 percent to $86.66.

Home Depot (HD) rose 3.4 percent to $50.60. The timing of its share repurchases will not have a material impact on the diluted earnings per share in that period, the retailer said.

Chesapeake Energy Corp. jumped 7.1 percent, the most since Aug. 11, to $18.21. The company is in advanced talks to sell pipelines to Global Infrastructure Partners for more than $4 billion, said two people with knowledge of the matter.

Iron Mountain Inc. surged 14 percent, the biggest gain in the S&P 500, to $32.32. The document-storage company approved a plan to convert to a real-estate investment trust and increased its quarterly dividend by 8 percent.