Ukraine and Russia: What you need to know right now

* Russian Deputy Foreign Minister Sergei Ryabkov said Moscow rejected the ideology of limited nuclear war, and any accusations to the contrary by the West were groundless, according to the RIA news agency. DIPLOMACY * The White House is expected as soon as Wednesday to announce around $1 billion worth of new weapons aid for Ukraine, including anti-ship rocket systems, artillery rockets, and rounds for howitzers.

Ukraine ignored a Russian ultimatum to surrender the eastern city of Sievierodonetsk on Wednesday as Washington urged NATO defence ministers weighing more military support for Kyiv not to lose focus, saying the stakes were too high. FIGHTING * Russia-backed separatists said a humanitarian corridor planned to take Ukrainian civilians from Sievierodonetsk's Azot plan to territory they control had been disrupted by Ukraine's shells * The governor of the Luhansk region said about 500 civilians remain on the grounds of Azot, including 40 children. * Ukrainian forces are suffering painful losses against Russian troops in both Sievierodonetsk and the Kharkiv region, President Zelenskiy said. * British military intelligence said Russian forces had likely taken fixed positions around Azot, while Ukrainian fighters could survive in underground parts of the plant. * Russian President Vladimir Putin likely still wants to capture much if not all of Ukraine but has had to narrow his tactical objectives in war, the U.S. Under Secretary of Defense for Policy said. * Russian Deputy Foreign Minister Sergei Ryabkov said Moscow rejected the ideology of limited nuclear war, and any accusations to the contrary by the West were groundless, according to the RIA news agency.

DIPLOMACY * The White House is expected as soon as Wednesday to announce around $1 billion worth of new weapons aid for Ukraine, including anti-ship rocket systems, artillery rockets, and rounds for howitzers. * Britain is considering sending additional anti-ship missiles to Ukraine, beyond the weapons it has already promised. * Chinese President Xi Jinping spoke by phone with Vladimir Putin, telling his Russian counterpart all parties should promote proper resolution of the crisis, Chinese state media reported. ECONOMY * Russia's invasion of Ukraine will create a global wheat shortage for at least three seasons by keeping much of the Ukrainian crop from markets, pushing prices to record levels, Kyiv's agriculture minister said. * U.S. President Biden said temporary silos would be built along the border with Ukraine, including in Poland, in a bid to help export more grain. * The United States will allow certain energy-related transactions with Sberbank, VTB Bank, Alfa-Bank and several other Russian entities to continue through Dec. 5, the U.S. Department of Treasury said. * Furniture giant IKEA said on Wednesday it would further scale its operations in Russia

NATO * Ukraine said the defenders of Sievierodonetsk wanted to know when weapons would arrive. "Brussels, we are waiting for a decision," a presidential aide said. * NATO Secretary General Stoltenberg said the alliance was "extremely focused on stepping up support," at a meeting of dozens of defense ministers in Brussels. * A NATO summit in Madrid later this month is expected to agree an assistance package for Ukraine that will help the country with the move from old Soviet-era weaponry to NATO standard gear, Stoltenberg said. (Compiled by Simon Cameron-Moore and Frank Jack Daniel)