KYIV, Ukraine (AP) — Poland has officially requested permission from Germany to transfer its Leopard 2 tanks to Ukraine where they can help fight Russia's invasion, Polish Defense Minister Mariusz Błaszczak said Tuesday.

Berlin has received Warsaw’s request, Błaszczak said in a tweet, though German officials did not immediately confirm that.

The development on possible tank deliveries came as Ukrainian authorities moved to crack down on corruption, with three senior officials announcing their exit Tuesday.

Błaszczak also appealed to Germany “to join the coalition of countries supporting Ukraine with Leopard 2 tanks” — a reference to recent pressure on Berlin to send some of its own tanks. Germany has hesitated to take that step, despite Ukraine's pleas.

"This is our common cause, because it is about the security of the whole of Europe!” Błaszczak tweeted.

NATO Secretary General Jens Stoltenberg on Tuesday called for the speedy delivery of new weapons to Ukraine, where a broad battlefield stalemate is expected to give way to new offensives in the spring.

“At this crucial moment in the war, we need to provide Ukraine with heavier and more advanced systems, and we need to do it faster,” Stoltenberg said Tuesday after talks with German Defense Minister Boris Pistorius in Berlin.

In Kyiv, meanwhile, the deputy head of Ukraine’s presidential office quit Tuesday after President Volodymyr Zelenskyy pledged to launch a staff shake-up amid high-level corruption allegations.

Kyrylo Tymoshenko, the deputy head of Ukraine’s presidential office, asked to be relieved of his duties, according to an online copy of a decree signed by Zelenskyy and Tymoshenko’s own social media posts. Neither gave a reason for the resignation.

Deputy Defense Minister Viacheslav Shapovalov also resigned, local media reported, alleging his departure was linked to a scandal involving the purchase of food for the Ukrainian Armed Forces. Deputy Prosecutor General Oleksiy Symonenko quit, too.

With Western allies pouring billions of dollars into Ukraine to help Kyiv’s fight against Moscow, Zelenskyy had pledged to weed out corruption which some observers have described as endemic. Zelenskyy came to power in 2019 on an anti-establishment and anti-corruption platform.

Tymoshenko joined the presidential office in 2019, after working on Zelenskyy’s media and creative content strategy during his presidential campaign.

Last year he was under investigation relating to his personal use of luxury cars. He was also among officials linked last September to the embezzlement of humanitarian aid worth more than $7 million earmarked for the southern Zaporizhzhia region. He has denied all the allegations.

On Sunday, a deputy minister was dismissed for being part of a network embezzling budget funds. Ukraine’s infrastructure ministry later identified the dismissed official as Vasyl Lozynsky, a deputy minister there.

Oleksandr Kubrakov, the infrastructure minister, said Lozynsky was relieved of his duties after Ukraine’s anti-corruption agency detained him while he was receiving a $400,000 bribe for helping to fix contracts related to restoring infrastructure facilities battered by Russian missile strikes.

In his nightly video address, Zelenskyy said that Ukraine’s focus on the war would not stop his government from tackling corruption.

“I want to be clear: There will be no return to what used to be in the past,” Zelenskyy said.

The anti-corruption drive is vital if Ukraine wants to advance its application for membership of the European Union. To gain EU membership, countries must meet a detailed host of economic and political conditions, including a commitment to the rule of law and other democratic principles.

Last June, the European Union agreed Thursday to put Ukraine on a path toward EU membership, acting with uncharacteristic speed and unity to pull the embattled country further away from Russia’s influence and bind it more closely to the West.

Ukraine has long aspired to join NATO, too, but the military alliance is not about to offer an invitation, in part because of the country’s corruption, shortcomings in its defense establishment, and its contested borders.

In other developments:

Russian shelling overnight killed one civilian and wounded two others near the eastern city of Bakhmut, the epicenter of the fighting in recent months, regional Gov. Pavlo Kyrylenko said Tuesday.

Russian forces also shelled nine towns and villages in the northern Sumy region, which borders Russia, killing a young woman and wounding three other people, local Gov. Dmytro Zhyvytskyy reported on Telegram.

He said the casualties all lived in the same house, which suffered a direct artillery hit.