Ukrainian Defense Minister Oleksii Reznikov said Friday the military is "ready" to launch a counteroffensive against Russian forces.

"It's up to the general staff and the command," Reznikov said during a press briefing in Kyiv. "We will do it as soon as there is God's will, the weather and the commanders' decision."

Ukraine has received Patriot missile defense systems from the United States as well as Germany and the Netherlands. The Ukrainian military has been trained on how to use the systems and "mastered" them within weeks, according to Reznikov.

"The exact number of batteries, I'm sorry, I won't say," he added. "Let the enemy guess."

Meanwhile, Ukrainian Foreign Minister Dmytro Kuleba urged the world not to consider or call the anticipated counteroffensive "a decisive battle." Speaking at a press conference in Odesa on Friday, Kuleba said the decisive battle is the one that will lead to the liberation of all occupied Ukrainian territories.

-ABC News’ Will Gretsky

One person was killed and 23 people, including a child, were wounded in a Russian missile strike in Mykolaiv early Thursday, Ukrainian President Volodymyr Zelenskyy said.

The missile struck a block that had apartments, houses and a historic building, according to Zelenskyy.

"The terrorists will not get away with this yet another crime against humanity," the president said in a statement.

-ABC News' Will Gretsky

Ukrainian President Volodymyr Zelenskyy spoke with Chinese President Xi Jinping in what was the two leaders' first official contact since January 2022, before Russia's invasion of Ukraine.

Xi announced that he will send a special envoy to visit Ukraine and "other countries" to work on a political solution.

"I believe that this call, as well as the appointment of Ukraine's ambassador to China, will give a powerful impetus to the development of our bilateral relations," Zelenskyy said in a statement on Twitter.

The Chinese government's official position still refuses to call the war an "invasion."

The call between the two leaders is said to have lasted an hour, according to Zelenskyy's office.

"Before the full-scale Russian invasion, China was Ukraine's number one trading partner. I believe that our conversation today will give a powerful impetus to the return, preservation and development of this dynamic at all levels," Zelenskyy said in a statement.

-ABC News' Karson Yiu, Cindy Smith and Will Gretsky

At least two people were killed and 10 injured after a Russian missile hit a Ukrainian museum Tuesday, officials said.

The local history museum is located in the city center of Kupiansk, in the Kharkiv region.

"The terrorist country is doing everything to destroy us completely. Our history, our culture, our people," Ukrainian President Volodymyr Zelenskyy said on social media while sharing a video that showed the damaged building. "Killing Ukrainians with absolutely barbaric methods."

Russia's security services have arrested an anti-Kremlin political commentator who the jailed Wall Street Journal reporter Evan Gershkovich met with shortly before his own arrest.

Yaroslav Shirshikov has said he spent two days showing Gershkovich around the city of Yekaterinburg during a reporting trip there a couple of weeks before Russia seized Gershovich.

Shirshikov said he had been due to meet with Gershkovich again the week the reporter was arrested in the city.

This morning, local media published video showing masked security officers detaining Shirshikov in his apartment and searching it.

A local news outlet cited a security services representative saying Shirshikov may have been arrested for posting comments cheering the assassinations of two ultra-nationalist pro-war figures, Daria Dugina and the blogger Vladen Tatarsky.

The site UralLive quoted a law enforcement source that Shirshikov was detained on a charge of “justifying terrorism”, which carries a maximum sentence of 7 years prison. It linked the charge to a social media post in which Shirshikov wrote he wasn’t sad over the death of Tatarsky, who was killed in a bomb attack in St. Petersburg this month.

Shirshikov spoke to several international media outlets including ABC following Gershkovich's arrest. He said that Gershkovich had acted entirely as a professional journalist in Yekaterinburg, conducting interviews openly and doing usual reporting.

Shirshikov is a critic of the Russian government and has spoken publicly about his opposition to the war in Ukraine.

-ABC News' Patrick Reevell