Anheuser-Busch InBev reported a better-than-expected rise in first-quarter core profit on Thursday and announced the sale of a Korean brewery, but warned of tougher cost comparisons in the rest of the year.

The world's largest brewer said earnings before interest, tax, depreciation and amortization (EBITDA) rose a like-for-like 25.9 percent to $2.79 billion, compared with the average $2.56 billion in a Reuters poll of 13 analysts.

The maker of Budweiser, Stella Artois and Beck's, reporting in U.S. dollars for the first time, said all areas delivered EBITDA margin expansion, led by North America, where it grew to 37.3 percent from 29.9 percent.

North America now accounts for about 40 percent of group revenue after InBev's $52 billion purchase last year of Anheuser-Busch. EBITDA there grew by a like-for-like 31.7 percent.

However, AB InBev cautioned: The remaining quarters of the year should not show similar organic EBITDA growth due to more difficult comparisons

The company said volumes were up 0.9 percent, against expectations of broadly flat and better than competitors.

That compares with a 1 percent volume fall for world number two SABMiller and 6.3 percent and 5 percent like-for-like drops for Heineken and Carlsberg , both heavily present in the depressed European market.

AB InBev also announced the planned divestment of Oriental Brewery in Korea to private equity firm Kohlberg Kravis Roberts & Co for $1.8 billion.

The deal, yielding a capital gain of $500 million, would be used to build down some of the $45 billion of debt AB InBev took on to fund its merger.

The company, which has set a target of bringing in merger savings of $2.25 billion over three years, said the first quarter had yielded $295 million.

AB InBev shares have more than doubled since a November low, when debt concerns and a rights issue weighed them down, and now trade at a price to projected 2009 ratio some 25-30 percent above European peers.

For some, this is justified by strong cash flow generation and cost savings. Others argue expected savings are already factored into the share price.

(Reporting by Philip Blenkinsop; Editing by Sharon Lindores)