BRUSSELS - Anheuser-Busch InBev , the world's largest brewer, forecast a challenging start to 2010 with U.S. volumes under pressure after mixed fourth-quarter results buoyed by a sharp increase in Brazilian sales.

The maker of Budweiser, Stella Artois and Becks sold some 2 percent less beer in the United States, where it has about half of the market, in the fourth quarter but achieved higher prices and cut costs.

Strong sales in key market Brazil, where AB InBev pushed its market share to 70 percent, and the strength of that country's real currency were behind a 5.1 percent hike in group sales, more than the market had expected.

The company's much-watched core profit (EBITDA) rose an underlying 11.5 percent to $3.11 billion in the fourth quarter, against the $3.27 billion average forecast in a Reuters poll of 15 analysts.

AB InBev said it achieved $235 million of savings in the fourth quarter from the 2008 merger of Belgium's InBev and U.S. Anheuser-Busch, bringing the full-year total to $1.11 billion.

The company had a 2009 savings target of $1.0 billion and of $2.25 billion by 2011. It kept this forecast, although some analysts had expected the brewer to set its sights higher.

Recession-hit consumers in mature, developed-world markets bought less beer last year but stomached higher prices. Brewers with greater emerging-market exposure registered gains and all focused on squeezing out savings.

Heineken , with some 70 percent of its profits from Europe and North America, reported a 6.7 percent drop in volumes in the fourth quarter, but Carlsberg's volumes stayed unchanged after declining in the first nine months.

Underlying beer volumes were also flat for SABMiller , the world's No.2 brewer.

(Reporting by Philip Blenkinsop; editing by Dale Hudson and Karen Foster)