Russia-Ukraine updates: Russian missiles hit close to nuclear reactors: IAEA director

Actor Ben Stiller, a goodwill ambassador for the United Nations High Commissioner for Refugees for the last five years, is visiting Ukraine to highlight the refugee crisis.

"I’m here meeting people forced to flee their homes due to the war in Ukraine. People have shared stories about how the war has changed their lives -- how they’ve lost everything and are deeply worried about their future," Stiller said Monday from Ukraine.

"Protecting people forced to flee is a collective global responsibility," he said. "We have to remember this could happen to anyone, anywhere."

Stiller was seen meeting with Ukrainian President Volodymyr Zelenskyy on Monday. Stiller told the actor-turned-president, "What you’ve done and the way that you’ve rallied the country and for the world, it’s really inspiring."

Stiller also met with displaced people in Poland.

-ABC News' Christine Theodorou

Serhiy Haidai, the head of the Regional Military Administration in Luhansk in eastern Ukraine, said the situation along the entire Luhansk front is "extremely" difficult with Russian forces "launching a large-scale offensive in our region."

"They have accumulated a sufficient number of reserves and today all the free settlements of the region are on fire," Haidai said.

The city of Lysychansk in the Luhansk Oblast has been coming under "massive" Russian fire all day, he said, with the number of victims unknown. He said Russian forces are advancing along the Lysychansk-Bakhmut highway and nearby settlements are under constant fire.

Haidai added that Ukrainian troops are only in control of the Azot chemical plant in Severodonetsk.

Monday marks the beginning of a "truly historic week" for Ukraine, as the country awaits a decision on its future within the European Union, Ukrainian President Volodymyr Zelenskyy said during his Sunday evening address.

"We will hear the answer from the European Union on the candidate status for Ukraine," Zelenskyy said. Last week, the European Commission backed Ukraine for EU candidate status. Now it is up to the European Council to confirm Ukraine's status, with a decision expected by the end of this week, the Ukrainian president said.

"I am convinced that only a positive decision meets the interests of the whole of Europe," Zelenskyy said.

He added that Ukraine -- and other European countries -- should expect increased hostility from Russia in the coming week.

"We are preparing. We are ready. We warn partners," he said.

But as combat units from both sides of the conflict remain committed to intense combat in the Donbas, they are likely experiencing dips in morale, the United Kingdom's Ministry of Defense stated in a Sunday intelligence update.

"Ukrainian forces have likely suffered desertions in recent weeks, however, Russian morale highly likely remains especially troubled," the ministry said.

As cases of whole Russian units refusing to carry out orders and armed stand-offs between officers and their troops continue to occur, Russian authorities are likely struggling to put legal pressure on the dissenters due to the invasion's official status as a 'special military operation', the UK report said.

Low Russian morale is driven by "perceived poor leadership, limited opportunity for rotation of units out of combat, very heavy casualties, combat stress, continued poor logistics, and problems with pay," according to the Defense Ministry. Many Russian personnel of all ranks also likely remain confused about the war's objectives, it said.

The U.K. Defense Ministry also said Monday the struggles of Russia's air force likely contributed to the exhaustion of Russian ground troops. "In the conflict to date, Russia's air force has underperformed," another intelligence update said on Monday.

"Its failure to consistently deliver air power is likely one of the most important factors behind Russia's very limited campaign success," the report stated. Despite boasting relatively modern and capable combat jets, Russia's air combat training has for years highly likely been heavily scripted and designed to impress senior officials, as opposed to fostering modern skill-sets, the Defense Ministry said.

As a result, Russian ground troops in Ukraine are becoming worn out while a heavy reliance on advanced cruise missiles has likely led to their stocks running low, the report concluded.

More shelters, less music

The Ukrainian Parliament on Sunday supported a bill on the construction of a network of bomb shelters across Ukraine, including in new buildings.

"The war has shown that there were few reliable shelters in Ukraine," said Olena Shulyak, a member of parliament.

Many of the existing shelters are not equipped with evacuation exits, lack access to water supply and sewerage systems, and are not adapted for food storage, Shulyak said on Telegram, adding, "Not to mention their ability to protect the population in the event of weapons of mass destruction."

The parliament topped off a busy weekend when it banned music by artists with Russian citizenship from being aired in public and in Ukrainian media to prevent the influence of "separatist sentiment in the population," according to the new bill.

A two-thirds majority of lawmakers agreed that Russian music would make the adoption of a Russian identity more attractive while weakening the Ukrainian state.

-ABC News' Edward Szekeres, Yuriy Zaliznyak, Max Uzol and Yulia Drozd

Ukrainian Foreign Minister Dmytro Kuleba said Sunday that his country's leaders are trying to get McDonald's to reopen its franchises in Ukraine, while the fast-food giant has sold off its restaurants in Russia in response to the Kremlin's invasion of Ukraine.

While people in Russia are eating knockoff McDonald's burger's now rebranded as “Tasty, and That’s It" -- Kuleba said in a Father's Day Facebook message that Ukrainians are getting closer to enjoying real Big Mac's and Quarter Pounders.

“After the war started the company, like many others, closed restaurants in Ukraine for security reasons," Kuleba wrote. "But we in the MFA are convinced the conditions are right for them to resume work and we’re actively persuading them to return."

He said that a few weeks ago, Ukrainian officials contacted McDonald's Ukrainian office and its U.S. headquarters in Chicago to open negotiations on the company resuming operations

"We also raised this issue in official contacts with the U.S. government, as McDonald's is one of most famous American brands. The process is moving along," Kuleba said.

There was no immediate response from McDonald's.

-ABC News' Max Uzol