Russia’s anti-trust office has given approval to India’s major exploration firm ONGC to acquire London-listed, Russia-focused oil firm Imperial Energy.

According to the sources, ONGC has agreed the acquisition of Imperial for US$ 2.6 billion in late August.

The sources further revealed that the proposed deal marks ONGC’s second investment in Russia, where the conglomerate already has 20 percent stake in the Sakhalin-1 oil and gas consortium headed by US major Exxon.