The danger of Russian air attacks remained high on Friday, Ukraine's military said, a day after Russian missiles and drones killed at least 11 people in what appeared to be a response to promises by Western allies to supply Ukraine with tanks.

Russian forces trained tank, mortar and artillery fire on more than 60 towns and villages on Thursday in an arc of territory extending from Chernihiv and Sumy regions in the north through Kharkiv region in the northeast and in the focal points of Russian attempts to advance in Donetsk region in the east - Bakhmut and Avdiivka.

Ukraine's army command said its forces had repelled Russian attacks in various places over the previous 24 hours and struck command and control points, a troop concentration, two artillery concentration areas and an ammunition depot.

Reuters could not verify battlefield reports.

On Thursday, air raid alarms sounded across Ukraine as Russia launched air strikes after Germany and the United States said they would send Ukraine dozens of modern tanks.

More tanks will come from Canada, Poland, Britain, Finland and Norway while several more allies including France, Spain and the Netherlands were considering sending tanks too.

Ukraine's military said it shot down 47 of 59 Russian missiles on Thursday. Russia also launched 37 air strikes, 17 of them using Iranian-made Shahed-136 drones. All drones were downed, the military said.

Eleven people were killed and 11 wounded in the drone and missile strikes, which spanned 11 regions and also damaged 35 buildings, a State Emergency Service spokesperson said.

"Not a single room is left intact, everything got hit," said Halyna Panosyan, 67, surveying twisted sheets of corrugated metal, crumpled masonry and a big missile crater outside her ruined house in Hlevakha near Kyiv.

"There was an extremely loud strike that made me jump up. I was in the bedroom ... I was saved by the fact that the bedroom is to the other side of the house."

Japan on Friday tightened sanctions against Russia in response to its latest wave of missile attacks in Ukraine.

ENERGY TARGETED

Rafael Grossi, head of the International Atomic Energy Agency (IAEA), who visited Ukraine last week, said IAEA monitors reported powerful explosions near Ukraine's Russian-occupied Zaporizhzhia nuclear power station and renewed calls for a security zone around the plant.

But Renat Karchaa, an adviser to the head of Rosenergoatom, the company operating Russia's nuclear plants, said the comments were unfounded and called it a "provocation".

Russia has in the past reacted to Ukrainian successes with massed air strikes that left millions without light, heat or water.

On Thursday, it appeared to follow that pattern. Prime Minister Denys Shmyhal said Russia's attacks targeted energy plants.

"Repair teams are working in those sites," President Volodomyr Zelenskiy said in an evening video address on Thursday.

The Kremlin said it saw the promised delivery of Western tanks as evidence of growing "direct involvement" of the United States and Europe in the 11-month-old war, something both deny.

Western allies have committed about 150 tanks while Ukraine has said it needs hundreds to break Russian defensive lines and recapture occupied territory in the south and east. Both Moscow and Kyiv, which have relied on Soviet-era T-72 tanks, are expected to mount new ground offensives in the spring.

After being promised modern tanks, Ukraine is now seeking Western fourth-generation fighter jets such as the U.S. F-16, an adviser to Ukraine's defence minister said.

In Odesa, the Black Sea port designated a "World Heritage in Danger" site on Wednesday by the U.N. cultural agency UNESCO, Russian missiles damaged energy facilities, authorities said, just as French Foreign Minister Catherine Colonna was arriving.

"What we saw today, new strikes on civilian Ukrainian infrastructure is not waging war, it's waging war crimes," she said.

The United States on Thursday formally designated Russian private military company the Wagner Group a transnational criminal organization, freezing its U.S. assets for helping Russia's military in Ukraine.

Since invading Ukraine on Feb. 24 last year, Russia has shifted the focus of its rhetoric from "denazifying" and "demilitarising" its neighbour to confronting what is says is an aggressive and expansionist U.S.-led NATO alliance.

Russia's invasion has killed thousands of civilians, uprooted millions and reduced cities to rubble.

Oleskandr Musiyenko, head of the Military and Strategic Research Centre of Ukraine, said Russia was sending in more reinforcements to block Ukrainian advances.

"They are mostly sending infantry and artillery forces into battle, made up mainly of conscripts. But they do not have the level of artillery and tank support they had on Feb. 24," Musiyenko said in an interview with Ukrainian television.

"They have fewer resources. They are relying on the numerical superiority of their troops."

(Reporting by Reuters bureaus; writing by Cynthia Osterman & Shri Navaratnam; Editing by Grant McCool, Robert Birsel)