The new U.S. ambassador to the United Nations, Nikki Haley, has expressed "strong condemnation of Russia's actions" in eastern Ukraine and warned that Ukraine-related sanctions against Russia will not be lifted until Crimea is returned to Kyiv.
"Crimea is a part of Ukraine. Our Crimea-related sanctions will remain in place until Russia returns control of the peninsula to Ukraine," she said on February 2 in her first public remarks before the Security Council since being sworn into office.
"Eastern Ukraine, of course, is not the only part of the country suffering because of Russia's aggressive actions. The United States continues to condemn and call for an immediate end to the Russian occupation of Crimea," Haley said.
The new American envoy said it was "unfortunate" that she had to condemn Russia in her first appearance before the council.
"We do want to better our relations with Russia," she said, but "the dire situation in eastern Ukraine is one that demands clear and strong condemnation of Russian actions."
Russia took control of Crimea in March 2014 after sending in troops and staging a referendum condemned by Ukraine and 99 other countries in the UN as illegitimate.
More than 9,750 people have been killed since the conflict between Kyiv’s forces and Russia-backed separatists erupted in the Donetsk and Luhansk provinces the following month.
Fighting has flared in the past week in the country's east, with heavy fighting between government forces and Russia-backed separatists entering its fifth day.
Ukrainian officials had earlier reported the deaths of eight soldiers in the past few days, a significant spike in casualties, and separatist fighters and civilians have also been killed and injured.
Russia and Ukraine have traded blame for the increase in violence. Russia's UN ambassador said observers have blamed the escalation on Ukrainian forces and he accused Ukraine of "desperately, frantically" trying to achieve a military victory.
Vitaly Churkin, echoing comments by Russian President Vladimir Putin earlier in the day, told the UN council late on February 2 that Kyiv needs money which it "can swindle out of the European Union, certain European countries, and from the United States and from international financial institutions by pretending to be the victims of aggression."
He called for a cease-fire and return to implementation of the Minsk peace agreement.
But U.S. Senator John McCain said Russia is testing President Donald Trump by escalating the violence in Ukraine. He dismissed Putin's accusations that Kyiv is fomenting the latest fighting in an effort to gain support from the new U.S. administration.
McCain, a senior Republican senator from Arizona and a regular critic of Trump as well as Russia, sent a letter to the president in which he urged him to provide lethal aid to Kyiv.
"That this surge of attacks began the day after [Putin] talked with you by phone is a clear indication that Vladimir Putin is moving quickly to test you as commander in chief. America's response will have lasting consequences," McCain said in the letter released by his office.
WATCH: Ukraine Fighting Rages For Fifth Day
Putin, speaking in Budapest after a meeting with Hungarian Prime Minister Viktor Orban, claimed "the Ukrainian leadership needs money, and the best way to get the EU, the U.S., and international organizations to pay is by posing as a victim of aggression."
WATCH: Putin Blames Kyiv For Escalation In Eastern Ukraine
Ukrainian President Petro Poroshenko issued a statement urging the international community to "more actively put pressure on Russia in order to end the shelling."
Ukraine has expressed concerns that Trump could roll back some sanctions imposed on Russia after its 2014 annexation of Ukraine's Crimea region and in retaliation for Moscow's military, economic, and political support for separatist militants in eastern Ukraine.
Trump has repeatedly expressed hope for improved relations with Moscow.
In Brussels, EU President Donald Tusk urged Russia to use its influence to "disengage the Russia-backed separatists" and to restore a cease-fire.
The Ukrainian military reported two soldiers killed overnight on February 2 and 10 wounded in shelling in the government-held town of Avdiyivka, just north of the separatist stronghold of Donetsk. The separatists said one of their fighters was killed.
"Moscow was putting Avdiyivka on the brink of a humanitarian catastrophe," Poroshenko's statement said.
WATCH: Intense Fighting Prompts Evacuations In East Ukraine
At least 15 people have been reported killed in the Avdiyivka area over the last five days.
More than 9,750 people have been killed since the conflict in eastern Ukraine erupted in April 2014.
With reporting by AP, TASS, and Reuters