Ukraine and Russia: What you need to know right now

* Russian President Vladimir Putin agreed "in principle" to U.N. and International Committee for the Red Cross involvement in the evacuation of civilians from a besieged steel plant in Ukraine's southern city of Mariupol, the United Nations said. FIGHTING Reports of battlefield developments below could not be immediately verified by Reuters: * Ukraine's general staff said Russian forces were pressing their offensive in the Kharkiv and Donetsk regions and they had captured several settlements.

Russian gas supplies to Poland were halted briefly, data from the European Union gas transmission operators showed, raising fears Russia may turn off the gas taps to Ukraine's allies in what it calls "gas blackmail". Bulgaria, like Poland a NATO and EU member, said earlier that Russia would also halt supplies of gas to it but a top energy official said supplies were flowing early on Wednesday.

SPILLOVER INTO MOLDOVA? * Ukraine accused Russia of trying to drag Moldova's breakaway region of Transdniestria into its war after authorities in the Russia-backed region, adjacent to southwest Ukraine, said they had been targeted by a series of attacks.

DIPLOMACY, AID * The United States hosted defense talks in Germany, involving over 40 countries, that sought to speed and synchronize the delivery of arms to Ukraine.

* Germany announced its first delivery of heavy weapons - Gepard tanks with anti-aircraft guns - to Ukraine after weeks of pressure at home and abroad. * Russian President Vladimir Putin agreed "in principle" to U.N. and International Committee for the Red Cross involvement in the evacuation of civilians from a besieged steel plant in Ukraine's southern city of Mariupol, the United Nations said.

FIGHTING Reports of battlefield developments below could not be immediately verified by Reuters:

* Ukraine's general staff said Russian forces were pressing their offensive in the Kharkiv and Donetsk regions and they had captured several settlements. * Ukraine retains control over the majority of its airspace, Britain's defense ministry said, adding that Russia has failed to effectively destroy Ukraine's air force or suppress its air defenses.

* Series of blasts were heard in the early hours of Wednesday in three Russian provinces bordering Ukraine, authorities said, and an ammunition depot in the Belgorod province caught fire around the same time. HUMAN AND ECONOMIC IMPACT

* Ukrainian authorities dismantled a huge Soviet-era monument in the center of Kyiv meant to symbolize friendship between Russia and Ukraine, a response to Moscow's invasion, according to the city's mayor. * Ukrainian farmers in the southern region of Zaporizhzhia that borders the front line are wearing body armor to plow their fields. Ukraine is the world's fifth-biggest exporter of wheat.

RUSSIAN WARNING * One of President Vladimir Putin's closest allies said Ukraine was spiraling towards a collapse into several states because of what he cast as a U.S. attempt to use Ukraine to undermine Russia.

QUOTES * "Nations from around the world stand united in our resolve to support Ukraine in its fight against Russia's imperial aggression." - U.S. Defense Secretary Lloyd Austin