DONETSK, Ukraine — The steadily advancing Ukrainian army is setting its sights on the largest rebel-held city in eastern Ukraine, while Western officials warned Wednesday that a Russian military buildup on Ukraine's border could herald a major incursion to protect the separatists.
President Vladimir Putin has resisted mounting pressure from Russian nationalists to send the army in to back up the mutiny in eastern Ukraine. The West would be certain to impose major sanctions that would put the shaky Russian economy on its knees and could quickly erode Putin's power.
Russia already is showing signs of economic dismay from sanctions imposed this year. Putin hit back Wednesday against countries that have imposed sanctions, ordering trade cuts that an official said would include a ban on all imports of agricultural products from the United States. The full list of products to be banned or limited for up to one year is to be published today.
U.S. and NATO officials say about 20,000 Russian troops are massed just east of Ukraine. Pro-Russian separatists in eastern Ukraine have been fighting the Kiev government since April.
The West has accused Russia of most likely providing the insurgents with surface-to-air missiles that may have been used to shoot down a Malaysia Airlines passenger jet over rebel-held territory July 17, killing all 298 people on board. The prime minister of the Netherlands, whose nationals made up more than half of the victims, said Wednesday that the search for remains is being halted because of fighting in the area.