lklv magnay Ukrainians brace for rebel attack_00001403.jpg
Ukrainians brace for rebel attack
01:02 - Source: CNN

Story highlights

Sen. Robert Menendez calls for the arming of Ukrainian forces.

Menendez says Russia has invaded Ukraine and it's time to help the Ukrainians fight back.

Ukraine's President Petro Poroshenko says conflict is inching toward "full-scale war."

Russia is still denying it has sent troops and weapons over the border.

Mariupol, Ukraine CNN  — 

Though Russia has denied sending its troops to Ukraine, it defended the rebels’ action in the east.

Sen. Robert Menendez, D-New Jersey, is in the Ukrainian capital of Kiev. He said the conflict in eastern Ukraine is not a rebel uprising, but a Russian invasion.

Appearing on CNN’s “State of the Union” on Sunday, Menendez called this a “watershed moment” in the conflict. He said it’s time to recognize what’s really happening in eastern Ukraine – not a rebel uprising, but a Russian invasion.

“And we must recognize it as that,” said Menendez, chairman of the Senate Foreign Relations Committee. “When I read the headlines back at home that suggest rebels are advancing in different parts of eastern Ukraine, it’s not rebels – it’s Russian soldiers.”

“We should be providing the Ukrainians with the type of defensive weapons that will impose a cost upon Putin for further aggression,” said Menendez, chairman of the Senate Foreign Relations Committee.

In the past, U.S. President Barack Obama has opposed supplying Ukraine with weapons. .

“I think the European Union, NATO, as well as the United States has to consider this is dramatically different and we have to give the Ukrainians the fighting chance to defend themselves. I’m not suggesting U.S. troops here or NATO troops here … but I am suggesting that the Ukrainians have the wherewithal to fight for themselves. “

Poroshenko warns of looming war with Russia

A top European Union official said Saturday that new sanctions will be proposed within a week against Russia over its actions in Ukraine, but Ukrainian President Petro Poroshenko sounded like he can’t wait that long.

“I think we are very close to the point of no return,” Poroshenko said Saturday following an EU summit in Brussels. “The point of no return is full-scale war, which already happened in the territory controlled by separatists and where – instead of separatists – there are regular Russian troops.”

Poroshenko said the situation had worsened in the last few days and that thousands of foreign troops and hundreds of foreign tanks are now on Ukrainian territory.

Russia has repeatedly denied either supporting the rebels or sending its own troops over the border. But those assertions have been roundly rejected by the West.

European Council President Herman Van Rompuy, speaking at the summit, said new sanctions will be proposed.

“The European Council says that it stands ready to take further significant steps in the light of the evolution of the situation on the ground and it requests the commission to urgently undertake preparatory work … and present proposals for consideration within a week,” Rompuy said.

Russian President Vladimir Putin appeared defiant in the face of a chorus of Western condemnation over what NATO says is clear evidence of Russian military aggression in Ukraine.

Moscow doesn’t want or intend to wade into any “large-scale conflicts,” Putin said Friday at a youth forum, state-run Itar-Tass reported. A few breaths later, he made the point that Russia is “strengthening our nuclear deterrence forces and our armed forces,” making them more efficient and modernized.

“I want to remind you that Russia is one of the most powerful nuclear nations,” the President said. “This is a reality, not just words.”

Port city fortifies

The Ukrainian military worked to fortify the port city of Mariupol after Russian intelligence groups were observed there, Col. Andriy Lysenko, spokesman for the Ukrainian National Defense and Security Council, said Saturday.

A CNN team saw Ukrainian forces strengthening defensive positions on the eastern outskirts of the city, reinforcing checkpoints and digging trenches along roads leading toward the Russian border.

Beyond these checkpoints, the team found a small advance detachment of Ukrainian troops on the main road about halfway between Mariupol and Novoazovsk. The soldiers said it had been quiet Saturday.

Denials ‘without credibility’

Russia annexed Ukraine’s Crimean peninsula in March, following the ouster of pro-Moscow President Viktor Yanukovych the previous month.

Violence broke out in the eastern Donetsk and Luhansk regions in April, as separatist leaders declared independence from the government in Kiev. Since mid-April, the conflict between the pro-Russia rebels and the Ukrainian military has cost more than 2,500 lives, according to the United Nations.

UNREST MAPPED: A divided Ukraine

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READ: Ukraine crisis: 6 questions and answers

CNN’s Tim Lister reported from Mariupol and Faith Karimi wrote and reported in Atlanta. CNN’s Barbara Starr and Greg Botelho and journalist Victoria Butenko in Kiev contributed to this report.