Ukrainian Foreign Minister Dmytro Kuleba on Tuesday criticized Germany for not sending his country Leopard tanks and Marder infantry fighting vehicles.

"Disappointing signals from Germany while Ukraine needs Leopards and Marders now — to liberate people and save them from genocide," Kuleba wrote on Twitter. 

"Not a single rational argument on why these weapons cannot be supplied, only abstract fears and excuses. What is Berlin afraid of that Kyiv is not?"

Germany has supplied Ukraine with military equipment, ammunition and anti-aircraft tanks. But critics say Berlin's support came late as it was initially reluctant to supply weapons to a conflict zone.

Berlin is now under pressure again as Ukraine presses ahead with a counteroffensive that saw Russia withdraw from key areas in the east. 

Still, the German government insists that it would only supply weapons in close coordination with its allies. 

Here's a roundup of some of the other key developments regarding Russia's invasion of Ukraine on September 13.

Power restored to Zaporizhzhia, Kharkiv

As the Ukrainian military made made advances in Kharkiv, power firm Ukrenergo said that repair crews had restored the two main power lines for the city following blackouts caused by Russian shelling.

In a statement, Ukrenergo said repair work on other lines would continue, but gave no further details.

At the same time, the International Atomic Energy Agency (IAEA) said it had restored all three of the backup powerlines of the Russian-held Zaporizhzhia nuclear power plant after a shutdown yesterday.

The plant has been held by Russia since early in the invasion, and damage to the plant from repeated shelling had prompted fears of a possible nuclear disaster. Earlier this month, Moscow's forces finally allowed IAEA specialists to enter the premises and assess the damage.

Scholz speaks with Putin by phone, urges cease-fire 

German Chancellor Olaf Scholz spoke with Russian President Vladimir Putin, calling for a diplomatic solution to Russia's invasion of Ukraine and demanding a cease-fire.

The Chancellor's office confirmed the call between the two leaders, saying it lasted 90 minutes. 

Scholz is said to have "urged" Putin to "come to a diplomatic solution as quickly as possible, based on a ceasefire, a complete withdrawal of Russian forces and respect for the territorial integrity and sovereignty of the Ukraine," according to the chancellor's spokesman Steffen Hebestreit. 

The German chancellor also spoke about the security at the Zaporizhzhia nuclear power plant, urging Putin to "avoid any escalation and implement in full the measures recommended by the International Atomic Energy Agency."

Russia says forces carrying out 'massive strikes' in Ukraine

Russian forces are launching strikes across eastern Ukraine, the Russian Defense Ministry said days after it pulled back its troops from some parts of Ukraine's northeastern Kharkiv region.  

"Air, rocket and artillery forces are carrying out massive strikes on units of the Ukrainian armed forces in all operational directions," the ministry said in its daily briefing on the conflict.

It added that "high-precision" strikes have also been launched on Ukrainian positions around Sloviansk and Konstantinovka in the eastern Donetsk region.

Moscow also accused Ukrainian forces of abusing civilians in territories it had recaptured. The allegation came after Kyiv said its troops found bodies of civilians with "signs of torture" in a village they recaptured in the east.

Russian forces 'severely weakened' as fighting continues in Kharkiv

Elements of the Russian army that have withdrawn from Kharkiv had not been "fully reconstituted" since suffering casualties in the beginning of the invasion, the latest UK military intelligence report said Tuesday.

According to the report, those elements were the "most prestigious of Russia’s armies" and intended to defend Moscow and lead Russian forces in the case of war with NATO.

"Russia's conventional force designed to counter NATO is severely weakened. It will likely take years for Russia to rebuild this capability," the British Defense Ministry said. 

The report comes after Ukraine launched a counteroffensive in Kharkiv, with Russia announcing withdrawing its troops from key areas of Kharkiv, including the strategically important city of Izium.

Fighting in Kharkiv continued on Tuesday, Ukraine's deputy defense minister Hanna Malyar told the Reuters news agency. 

"The aim is to liberate the Kharkiv region and beyond - all the territories occupied by the Russian Federation. Fighting is continuing [in Kharkiv]. It is still early to say full [Ukrainian] control has been established over Kharkiv region," Malyar said in an interview.

Ukraine's President Volodymyr Zelenskyy renewed his calls for Western deliveries of weapons systems as he claimed his army had now recaptured roughly 6,000 square km (2,400 square miles) of territory. 

Kyiv claims downing Iranian-made drone

A Ukrainian military official published on Telegram photos of wreckage of a drone that he claimed was Iranian-made and used by Russian forces. The images implied that it was shot down but did not detonate, however, there were no further information released by Kyiv. 

The official, as well as a pro-Ukrainian military website, said that Ukraine's forces had encountered the suicide drone near the city of Kupiansk in Kharkiv. 

Tehran and Moscow have had strong ties, with their military partnership growing since the start of a decade-old conflict in Syria.

Iranian officials have also recently boasted arming the world's top powers.

In July, Washington warned that Iran was planning on sending bomb-carrying drones to Russia to support its war in Ukraine. 

fb,es/aw (Reuters, AP)