UPDATE 1-Salini raises Impregilo stake to 20 pct

* Stake is worth about 210 mln euros

* Battle for control of Impregilo

MILAN Feb 15 (Reuters) - Italian construction group Salini said on Wednesday it had raised its stake in rival Impregilo to 20.06 percent from 15 percent in less than two months , a move that could heat up the battle to control Italy's biggest builder.

Family-owned Salini aims to merge with Impregilo's construction operations to create an Italian construction champion with 5 billion euros in annual sales.

"Salini reaffirms its strategic priority to build, over time, a leading European-based construction and concessionary group with the scale and expertise to compete in the global infrastructure sector," the group said in a statement.

Its ambitions are opposed by the Gavio family, which controls Impregilo with the Benetton family and has close links to powerful investment bank Mediobanca.

Salini's stake in Impregilo is worth about 210 million euros ($274 million).

In January, a source close to the matter said Salini was mulling options ranging from a friendly merger with Impregilo to a bid for the company.

On the other side, the Gavios are finalising talks with the Benettons to raise their Impregilo stake to nearly 30 percent, other sources close to the matter said last week.

The Gavios and the Benettons share control of IGLI, a shell company that has 29.9 percent of Impregilo. Their IGLI stakes are held via Argo Finanziaria and Atlantia, respectively.

Shares in Impregilo closed up 2.7 percent to 2.6 euros on Wednesday, outperforming a 0.2 percent gain in the Europe construction index.