Electronic Arts is expanding its grip on the mobile gaming market with its acquisition today of Hands-On Mobile Korea for an undisclosed price.

The deal gives EA a strong presence in the fast-growing South Korean mobile games market, adding to the strong share EA Mobile already has in the U.S. and Europe.

Hands-On Mobile Korea’s hot game is Heroes Lore. EA did not buy the rest of San Francisco-based Hands-On Mobile (formerly known as Mforma), the owner of Hands-On Mobile Korea.

Hands-On has raised more than $100 million in venture backing since its founding in 2001. Its investors include Bessemer Venture Partners, Draper Fisher Jurvetson, General Catalyst Partners, eFund and Institutional Venture Partners.

EA Mobile revenues were $155 million for the year ended March 31, 2008, about 4 percent of EA’s overall revenues. In the first calendar quarter of 2008, EA said its mobile revenues were 18 percent higher than its nearest competitor.

The deal will give EA Mobile a stronger international footprint and put pressure on rivals such as Digital Chocolate, Glu Mobile, and GameLoft.