Brussels/Donetsk: Russia has massed around 20,000 combat-ready troops on Ukraine's border and could use the pretext of a humanitarian mission to invade, Nato said on Wednesday, its starkest warning yet that Moscow could soon mount a ground assault against its neighbour.
With fighting escalating and rebels losing ground in the weeks since a Malaysian airliner was shot down over separatist-held territory, Russia has announced military exercises this week in the border region.
"We're not going to guess what's on Russia's mind, but we can see what Russia is doing on the ground — and that is of great concern. Russia has amassed around 20,000 combat-ready troops on Ukraine's eastern border," Nato spokeswoman Oana Lungescu said in an emailed statement.
Moscow could use "the pretext of a humanitarian or peace-keeping mission as an excuse to send troops into Eastern Ukraine", she said.
The latest Russian troop build-up on the border is not the first time Moscow has concentrated forces there: Nato estimated Russia had as many as 40,000 troops in place earlier in the crisis before President Vladimir Putin pulled them back in June.
Meanwhile, Putin on Wednesday banned or limited food and agricultural product imports for a year from nations that have imposed sanctions on Russia over its stance on Ukraine.
The Kremlin said in a statement that Putin's executive decree "either bans or limits... the import into the Russian Federation of certain kinds of agricultural products, raw materials and food originating from countries that have decided to adopt economic sanctions against Russian entities and individuals."
Government spokeswoman Natalia Timakova told the state-run RIA Novosti news agency that ministers were currently drafting the list of goods intended for future import restriction.
Deputy Agriculture Minister Alexei Likhachyov separately told the Interfax news agency that his draft of the list was already completed.
State statistics show Russia having imported about a third of its food from abroad in the past decade. Some of those deliveries come from ex-Soviet nations with strong ties to Moscow.