THE HAGUE, Netherlands (AP) -- With no sign of Russia abandoning the Crimean Peninsula, President Barack Obama said Tuesday he's concerned that Moscow will move deeper into Ukraine and warned Russian President Vladimir Putin that the international community is prepared to impose punishing sanctions against his country's economy.
Obama stood fast on his insistence that Crimea remains a part of Ukraine, even as the fledgling Ukrainian government in Kiev ordered its troops to pull back from the disputed territory. He dismissed Russia as a "regional power" that was acting from a position of weakness.
"We're not recognizing what is happening in Crimea," Obama said at his first news conference since Russia moved to annex Crimea after a referendum 10 days ago. Obama rejected "the notion that a referendum sloppily organized over the course of two weeks" would "somehow be a valid process."
Obama said that while the Russia's military controls Crimea, its acquisition of the Black Sea peninsula is "not a done deal" without international recognition. But he also said, "It would be dishonest to suggest there is a simple solution to what has already taken place in Crimea."
"We also are concerned about further encroachment by Russia into Ukraine," Obama said, as he took questions in a joint appearance with his host, Dutch Prime Minister Mark Rutte.
"I think that will be a bad choice for President Putin to make," Obama said. "But ultimately he is the president of Russia, and he's the one who's going to be making that decision."
Obama was pursuing efforts to pressure Russia out of its aggressive pose as world leaders met for an international Nuclear Security Summit. But to the east, the Russian annexation of Crimea was beginning to take root and Moscow shrugged off Obama's drive to leave Putin in the cold.
Rutte said he could not envision the crisis over Ukraine ending in a military conflict. "I don't think that is likely. I don't think anybody wants it," the Dutch prime minister said as he stood next to Obama.
Rutte added that the West retains the option to impose more sanctions on Russia if the standoff escalates, and he said that "these sanctions would hit Russia very badly."
"And obviously, you can never guarantee that the people in Europe, in Canada, in the U.S. would not be hurt," the prime minister said. "But obviously, we will make sure that we will design these sanctions in such a way that they will have maximum impact on the Russian economy and not on the European, the Canadian, the Japanese or the American economy."
Obama also said he was concerned about Russia's troop build-up along the Ukrainian border. "We oppose what appears to be an effort at intimidation," Obama said. "But Russia has a right legally to have its troops on its own soil."
Asked whether in hindsight he agrees with Republican presidential challenger Mitt Romney's assessment that Russia is the United States' top geopolitical foe, Obama said he is more concerned about a nuclear bomb in Manhattan than he is about Russia's actions threatening national security.
"America's got a whole lot of challenges," Obama said. "Russia is a regional power that is threatening some of its immediate neighbors, not out of strength but out of weakness."
The U.S. and some of its closest allies cut Russia out indefinitely from an exclusive coalition of leading industrial nations and canceled a summer summit Russia was to host in its Olympic village of Sochi. Obama also sought to win backing from other foreign leaders in hopes of ostracizing or even shaming Putin into reversing his acquisition of Crimea and backing away from any designs he might have on other Eastern Europe territory.
In a strongly worded joint statement, the United States, France, Canada, Britain, Germany, Italy and Japan denounced a referendum in Crimea to secede from Ukraine and Russia's ensuing annexation. In so doing, the seven leaders also effectively excluded Russia from what had been a two-decade-old coalition known as the Group of Eight.
"This clear violation of international law is a serious challenge to the rule of law around the world and should be a concern for all nations," the declaration said.
Still, Russian Foreign Minister Sergei Lavrov shrugged off the international gestures.
"The G-8 is an informal club," he said. "It has no membership tickets, and it can't purge anyone by definition."
In an addition to his public schedule, Obama sat down with Putin ally President Nursultan Nazarbayev of Kazakhstan. As Obama and Nazarbayev wrapped up their meeting, the White House released a joint statement from Obama and Nazarbayev that did not address the Ukraine situation, but focused instead on bilateral cooperation on nuclear security - the theme of concurrent summit serving as the official purpose for Obama's visit to the Netherlands.
Obama praised action at the summit, including new commitments by Japan, Italy and Belgium to reduce their stocks of nuclear materials. He said the next summit, in 2016, will be held in the U.S.
Later Tuesday, Obama met with Prince Mohamed bin Zayed, crown prince of Abu Dhabi, the richest emirate in the United Arab Emirates federation. He was also scheduled to meet jointly with Japanese Prime Minister Shinzo Abe and South Korean President Park Geun-hye.
Both those meetings centered less on Ukraine and more on regional tensions in the Middle East and northern Asia. The visit with the crown prince served as precursor to Obama's on Friday visit to Saudi Arabia, where he will meet with King Abdullah to address Arab anxieties over the Syrian civil war and U.S. nuclear talks with Iran, a Saudi rival in the region.
The meeting with Park and Abe brings together two U.S. Asian allies who have been quarreling over rekindled memories of Japan's aggression in World War II. It will be the first meeting between the two Asian leaders since they took office more than a year ago.