KYIV, Ukraine (AP) The Kremlin said rebels in eastern Ukraine asked Russia for military assistance Wednesday to help fend off Ukrainian aggression, an announcement that immediately fueled fears that Moscow was offering up a pretext for war, just as the West had warned about.

A short time later, the Ukrainian president rejected Moscows claims that his country poses a threat to Russia and warned that a Russian invasion would cost tens of thousands of lives.

The people of Ukraine and the government of Ukraine want peace, President Volodymyr Zelenskyy said in an emotional overnight address to his nation in Russian. But if we come under attack, if we face an attempt to take away our country, our freedom, our lives and lives of our children, we will defend ourselves. When you attack us, you will see our faces, not our backs.

Zelenskyy said he asked to arrange a call with Russian President Vladimir Putin late Wednesday, but the Kremlin didnt respond.

In an apparent reference to Putins move to sanction the deployment of the Russian military to maintain peace in eastern Ukraine, Zelenskyy warned that this step could mark the start of a big war on the European continent.

Any provocation, any spark could trigger a blaze that will destroy everything, he said.

He challenged the Russian propaganda claims, saying that you are told that this blaze will bring freedom to the people of Ukraine, but the Ukrainian people are free.

The United Nations Security Council quickly scheduled an emergency meeting Wednesday night at Ukraines request. Ukrainian Foreign Minister Dmytro Kuleba called the separatists request a further escalation of the security situation.

Anxiety about an imminent Russian offensive against its neighbor soared after Putin recognized the separatist regions independence on Monday, sanctioned the deployment of troops to the rebel territories to help maintain peace and received parliamentary approval to use military force outside the country. The West responded with sanctions.

Kremlin spokesman Dmitry Peskov said the rebel chiefs wrote to Putin Wednesday, pleading with him to intervene after Ukrainian shelling caused civilian deaths and crippled vital infrastructure.

White House press secretary Jen Psaki said the separatists request for Russian help was an example of the sort of false-flag operation that the U.S. and its allies have expected Moscow to use as a pretense for war.

So well continue to call out what we see as false-flag operations or efforts to spread misinformation about what the actual status is on the ground, she said.

The U.S. and key European allies accused Moscow of crossing a red line Tuesday in rolling over Ukraines border into a separatist eastern region known as the Donbas, with some calling it an invasion.

Earlier in the day, Ukrainian lawmakers approved a decree that imposes a nationwide state of emergency for 30 days starting Thursday. The measure allows authorities to declare curfews and restrictions on movement, block rallies and ban political parties and organizations in the interests of national security and public order.

The action reflected increasing concern among Ukrainian authorities after weeks of trying to project calm. The Foreign Ministry advised against travel to Russia and recommended that any Ukrainians who are there leave immediately.

Russia on Wednesday evacuated its embassy in Kyiv as hopes for a diplomatic way out of a new, potentially devastating war in Europe waned.

For a long time, we refrained from declaring a state of emergency ... but today the situation has become more complicated, National Security and Defense Council head Oleksiy Danilov told parliament, emphasizing that Moscows efforts to destabilize Ukraine represented the main threat.

Pentagon press secretary John Kirby said the Russian force of more than 150,000 troops arrayed along Ukraines borders is in an advanced state of readiness. They are ready to go right now, Kirby said.

The latest images released by the Maxar satellite image company show Russian troops and military equipment deployed within 10 miles of the Ukrainian border and less than 50 miles from Ukraines second-largest city, Kharkiv.

In response to Russias action, President Joe Biden allowed sanctions to move forward against the company that built the Russia-to-Germany Nord Stream 2 gas pipeline and against the companys CEO.

Today, I have directed my administration to impose sanctions on Nord Stream 2 AG and its corporate officers, Biden said in a statement. As I have made clear, we will not hesitate to take further steps if Russia continues to escalate.

Germany said Tuesday it was indefinitely suspending the project, after Biden charged that Putin had launched the beginning of a Russian invasion of Ukraine by sending troops into the separatist regions. The pipeline is complete but has not yet begun operating.

Putin said Tuesday he hadnt yet sent any Russian troops into the rebel regions contrary to Western claims, and Donetsk rebel leader Denis Pushilin insisted Wednesday there were no Russian troops in the region even though a local council member claimed the previous day they had moved in.

Ukrainian Minister for Digital Transformation Mykhailo Fedorov said a wave of denial-of-service attacks targeted official websites and some banks Wednesday. The attacked knocked offline the sites of the parliament, cabinet and Foreign Ministry and caused interruptions or delays to the sites of the defense and interior ministry, which controls the police.

Already, the threat of war has shredded Ukraines economy and raised the specter of massive casualties, energy shortages across Europe and global economic chaos.

Even as the conflict took a new, dangerous turn, leaders warned it could still get worse . Putin has yet to unleash the force of the 150,000 troops massed on three sides of Ukraine, while Biden held back on even tougher sanctions that could cause economic turmoil for Russia but said they would go ahead if there is further aggression.

In other developments, Kyiv recalled its ambassador to Russia and considered breaking all diplomatic ties with Moscow; dozens of nations further squeezed Russian oligarchs and banks out of international markets; the U.S. repositioned additional troops to NATOs eastern flank bordering Russia; and the top U.S. diplomat canceled a meeting with his Russian counterpart.

European Union sanctions against Russia took effect, targeting several companies along with 351 Russian lawmakers, who voted for a motion urging Putin to recognize the rebel regions, and 27 senior government officials, business executives and top military officers.

The Russian Foreign Ministry has shrugged off the sanctions, saying that Russia has proven that, with all the costs of the sanctions, it is able to minimize the damage.

In Ukraines east, violence spiked again. One Ukrainian soldier was killed and six more were injured after rebel shelling, the Ukrainian military said. Separatist officials reported several explosions on their territory overnight and three civilian deaths.

Facing a barrage of criticism at the 193-member United Nations General Assembly, Russias U.N. ambassador Vassily Nebenzia warned Ukraine that Russia will monitor the cease-fire in the east and emphasized that no one intends to go softly, softly with any violators.

A new military adventure by Kyiv might cost the whole of Ukraine very dearly, he warned ominously.

After weeks of rising tensions, Putins steps this week that dramatically raised the stakes. He recognized the independence of those separatist regions , a move he said extends even to the large parts of the territories now held by Ukrainian forces, and had parliament grant him authority to use military force outside the country.

Putin laid out three conditions that he said could end the standoff, urging Kyiv to recognize Russias sovereignty over Crimea, the Black Sea peninsula that Moscow annexed from Ukraine in 2014, to renounce its bid to join NATO and to partially demilitarize. Ukraine long has rejected such demands.

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Litvinova reported from Moscow. Angela Charlton in Paris; Frank Jordans in Berlin; Lorne Cook in Brussels, Vladimir Isachenkov in Moscow, Frank Bajak in Boston, Robert Burns, Matthew Lee, Aamer Madhani, Eric Tucker, Ellen Knickmeyer, Zeke Miller, Chris Megerian and Darlene Superville in Washington contributed.