The alliance's secretary-general, Anders Fogh Rasmussen, said ambassadors for the 28 member states decided after a meeting with their Russian counterpart to suspend plans for a joint mission as well as all civilian and military meetings.
Rasmussen said that because of Russia's military action in the Crimean Peninsula, "the entire range of NATO-Russia cooperation (is) under review." Rasmussen said NATO will continue to meet with Moscow at the political level but insisted that halting all other cooperation "sends a very clear message to Russia."
One key piece of leverage that the West has over nearly bankrupt Ukraine: hard cash. The three months of protests that triggered Ukraine's crisis erupted when President Viktor Yanukovych accepted $15 billion in aid from Putin in exchange for dropping an economic partnership deal with the EU. On Wednesday, the EU matched the aid — which the Russians withdrew after Yanukovych's downfall — and the U.S. topped that up with an additional $1 billion.
Meanwhile, Ukraine's former prime minister — the heroine of Ukraine's 2004-2005 Orange Revolution and Yanukovych's arch-enemy — called on the West to force Russia to withdraw troops from Crimea.
Yulia Tymoshenko, who was released from prison two weeks ago, said any negotiations about Ukraine's future should be conducted directly between the U.S., the EU and Russia — and insisted no compromises should be made to appease Moscow.
"We believe that the aggressor must leave without any conditions," Tymoshenko told the AP in an interview.
The EU on Wednesday also froze the assets of 18 people held responsible for misappropriating state funds in Ukraine, echoing similar action in Switzerland and Austria.
Russia has suggested that it will meet any sanctions imposed by Western governments with a tough response, and Putin has warned that those measures could incur serious "mutual damage."
In Crimea, U.N. special envoy Robert Serry was threatened by 10 to 15 armed men as he was leaving naval headquarters in Crimea, said U.N. deputy secretary-general Jan Eliasson. When the men ordered Serry to go to the airport, Serry refused — but then found himself trapped because his car was blocked, Eliasson said.
The Dutch envoy was later spotted by reporters in a coffee shop, as men in camouflage outfits stood outside. He got into a van with the men, and was taken to Simferopol airport.
Later, an AP reporter found Serry in the business class lounge of the Simferopol airport.
"I'm safe. My visit was interrupted for reasons that I cannot understand," the Dutch diplomat said.
The Obama administration also said it was taking steps Wednesday to support the defenses of U.S. allies.
Defense Secretary Chuck Hagel told the Senate Armed Services Committee the U.S. was stepping up joint aviation training with Polish forces and increasing American participation in NATO's air policing mission in ithe Baltics.
Meanwhile, the Organization for Security and Cooperation in Europe sent a team of 35 unarmed military observers to Crimea on Wednesday at the fledgling government's request.
Danilova reported from Kiev. Associated Press writers Juergen Baetz in Brussels, Laura Mills in Moscow, Monika Scislowska in Warsaw, Poland, Greg Keller, and Sylvie Corbet in Paris, Julie Pace in Washington, and Pan Pylas in London contributed.
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