The big picture: Everything you need to know at the start of the week
By Katie Williams, live reporter
It's just gone midday at the start of another week in the Ukraine war.
While diplomacy once again takes centre stage, thousands are still suffering in the meantime - with Russia's war showing no sign of ending any time soon.
Let's step back from the news of the day to ensure you're up to date on the biggest developments.
Peace talks
A year-long effort by Donald Trump's administration to push both sides towards a peace settlement doesn't look like coming to a conclusion soon, despite hints of progress.
Several rounds of talks have been taking place in the most recent diplomatic push to end the war, which will enter its fifth year later this month if no peace deal is struck.
Envoys from Russia, Ukraine and the US met in Abu Dhabi for landmark trilateral discussions last weekend. Though the talks were said to be constructive, they led to no new movement on the question of territory, which continues to be a major obstacle in negotiations.
Moscow is demanding that Kyiv cede the entire eastern Donbas region to Russia - a demand Ukraine says it will not accept.
The next trilateral talks were scheduled to take place on Sunday, 1 February, but Zelenskyy announced they would be delayed to later this week.
Attacks continue
That delay comes as Russia continues to pummel Ukraine with drone and missile strikes.
According to Zelenskyy, Moscow's forces launched 6,000 drones and around 5,500 guided aerial bombs at his country in January alone - virtually all of which were targeting Ukraine's energy sector, railways and infrastructure.
The Ukrainian leader says Russia is attempting to disrupt logistics and connectivity between cities and communities with its attacks.
On Friday, both sides said they would pause strikes on each other's energy infrastructure at Donald Trump's request - but there was uncertainty over the terms, and yesterday Russian strike killed 12 people on a bus carrying coal miners in Ukraine's Dnipro region.
Energy crisis
Attacks on Ukraine's energy grid are putting the country under pressure as it grapples with its harshest winter in four years of war.
Temperatures in some areas are set to drop below -20C this week, and with energy infrastructure compromised by constant strikes, life is set to be tough for Ukrainian people for days and weeks to come.
Two Russian missile and drone attacks on the capital city of Kyiv last month left around one million people without electricity and more than 5,000 homes without heat in freezing temperatures.
Zelenskyy confirmed yesterday that more than 500 apartment buildings were still without heat - and said "not enough" was being done by city authorities to combat the crisis.
Battlefield situation
While Russia maintains its aerial attacks, Ukrainian forces are also struggling to thwart grinding Russian advances on the battlefield.
In the last week or so, Russia claims to have captured several Ukrainian villages in various frontline regions - claims that have not been independently verified.
But despite its advances, Russia is expelling a large amount of resources "for minimal gains" on the battlefield, according to new analysis from the Centre for Strategic and International Studies (CSIS).
In a new report, CSIS says Russia has suffered an estimated 1.2 million casualties, including as many as 325,000 deaths, while Ukrainian forces have likely suffered somewhere between 500,000 and 600,000 casualties, including killed, wounded and missing.
The analysis also suggests Moscow's forces are advancing in Ukraine at the slowest pace seen in more than 100 years of warfare.