The city of Mariupol in southeastern Ukraine is without power or water after more than a week of heavy shelling and aerial attacks from Russian forces, Serhiy Orlov, deputy mayor of Mariupol, said in a press briefing Wednesday.

More than 1,200 Mariupol residents have been killed in the bombardments, Orlov said, adding that half of those killed are ethnic Russians whom Russia claims it is saving.

A huge steel mill that employs 30,000 people and a maternity hospital with 600 beds are among the obliterated structures in the strategic port city, Orlov said.

Orlov accused Russia of indiscriminately bombarding the city because its forces were unable to break through its defenses, saying that Mariupol would not surrender and calling on the outside world to help save it by imposing a "no-fly" zone.

"We understand that Mariupol was a showroom of free Ukraine -- a dynamic bustling city compared to ghost towns of the so-called DNR," Orlov said. "We must not fall. We must win and then rebuild. We can only live and develop in a free and independent Ukraine."

-ABC News' Patrick Reevell

Roughly 180,000 people have been evacuated to Russia from Ukraine, including the Russian-controlled areas of Luhansk and Donetsk in the Donbas region, according to the Russian Defense Ministry.

"As many as 5,460 people, including 1,125 children, have been evacuated from dangerous zones in various regions of Ukraine, as well as the Luhansk and Donetsk people's republics, without participation of the Ukrainian side over the past 24 hours, Mikhail Mizintsev, head of the Russian National Defense Control Center, said Wednesday. "Over 179,000 people, including 45,436 children, in total have already been [evacuated] since the beginning of the special military operation."

Mizintsev said a total of 20,961 vehicles crossed the state border of the Russian Federation, including 867 over the past day.

Mizintsev said of the citizens who evacuated to Russia, 166 were from Turkey, 41 Ukraine, 11 Egypt, eight Italy, seven Azerbaijan, six Pakistan, five India, as well as Swedish, Moroccan, and Brazilian citizens.

The U.N. High Commissioner for Refugees (UNHCR) said earlier Wednesday it has tallied 2.15 million people that have been evacuated from Ukraine since the Russian invasion began on Feb. 24, with more than half going to Poland.

Russian forces have closed in further on Kharkiv, gaining about 20 kilometers, about 12 miles, since Tuesday, a senior U.S. defense official told reporters at a press briefing Wednesday.

"It's still heavy, heavy fighting there," the official said on Day 14 of the Russian invasion. However, the U.S. does not believe Russia has "taken the city by any means," the official added.

The U.S. has not seen any significant movement toward Kyiv or Chernihiv since Tuesday, and there is still no sign of an any immanent amphibious assault on Odessa, the official said.

In southeast Ukraine, Mariupol remains isolated. Ukrainians are putting up stiff resistance, while Russians continue to bombard the city, the official said.

Russia has about 90% of its available combat power still intact, the official said. It has now launched more than 710 missiles against Ukraine -- about half being launched from within Ukraine and half being launched from within Russia, the official said.

-ABC News' Matt Seyler

Russia is retaining a temporary ceasefire in humanitarian corridors in Ukraine, head of the Russian National Defense Control Center Col. Gen. Mikhail Mizintsev alleged on Wednesday.

Ten of the corridors were proposed by Moscow, while three were proposed by Kyiv, Mizintsev told reporters at a press briefing.

"Today, at exactly 10 a.m. local time, in accordance with agreements reached on 10 humanitarian corridors initiated by the Russian Federation and three more at the request of the Ukrainian side, the Russian Armed Forces introduced a temporary ceasefire, which is being strictly observed until now," Mizintsev said

No practical measures for the preparation of humanitarian convoys have been carried out so far, and no one has ever arrived at the humanitarian corridors that have been opened, Mizintsev said. The formation of organized humanitarian convoys has also not been recorded, he claimed.

The Russian forces charging toward Kyiv haven't made progress in the last day as they face Ukrainian resistance and low food and gas supply, a senior U.S. defense official told reporters Tuesday.

However, it could be a deliberate pause, the official said. "Part of the stall could be ... as a result of their own self-determined sort of pause in operations -- that they are possibly regrouping, rethinking, reevaluating," the official said.

The U.S. believes Russian forces "have committed now more than 80% of what was their pre-staged combat power," the official added.

The official said some Russian soldiers weren't told they were going into combat. The official said "not all of them were apparently fully trained and prepared."

The strong Ukrainian resistance has also hurt morale, according to the official.

Russia has now launched more than 400 missiles on Ukraine, the official said. The U.S. believes Russia has launchers that could be used for thermobaric weapons, but cannot confirm their use, the official said.

Russian forces are making the most progress in the south. Russians are attacking Kherson in south Ukraine, which "appears very much to be contested city at this point," the official said.

Russians are also approaching Mariupol in southeastern Ukraine, and while they haven't yet entered the city, "they are close enough now that they could attack Mariupol with long range fires," the official said.

Two towns on the path to Mariupol are believed to be occupied by the Russians, according to the official.

The U.S. believes the Russians hope to move north out of Mariupol up to the heavily-contested city of Kharkiv. The official said they believe Russian forces are trying to encircle Kharkiv.

The U.S. official noted that they've seen "certain risk-averse behavior by the Russian military" over the last week.

"Take the amphibious assault, for instance. They put those troops ashore a good 70 kilometers away from Mariupol because they knew Mariupol was going to be defended and they could put them ashore in an uncontested environment. And they still haven't reached Mariupol," the official said.

"They are not necessarily willing to take high risks with their own aircraft and their own pilots," the official said.

"And of course we're seeing that on the ground -- the fairly slow and steady progress that they have made, and you guys are seeing it for yourselves on the ground where ... units are surrendering, sometimes without a fight."

-ABC News' Matt Seyler