DONETSK, Ukraine (AP) — Russia's foreign minister is promising a firm response if any of Russia's citizens or interests come under attack in Ukraine.

The warning came after Ukraine announced a resumption of what it calls an "anti-terror" campaign against pro-Russian insurgents who are occupying buildings in the eastern part of the country.

Foreign Minister Sergey Lavrov (SEHR'-gay LAHV'-rahf) did not specifically say Russia would launch a military attack. But his comments added to concerns that Russia could use any violence in eastern Ukraine as a pretext for sending in troops. Large contingents of Russian troops are in place near the Ukrainian border.

Yesterday's order from Ukraine's acting president to resume the "anti-terror" operation came after the bodies of two people allegedly abducted by pro-Russia insurgents were found.

The insurgents who are continuing to occupy public buildings are defying last week's international agreement in Geneva. It also called for all sides to disarm militant groups in Ukraine.