Aid workers blocked from beseiged Ukraine city Mariupol

Ukraine's south-eastern port city of Mariupol continues to bear the brunt of a sustained Russian bombardment.
Each day seems to brings its own fresh horror for the surrounded city, where more than 300,000 thousand people remain trapped.
Overnight there was more as Russia try to open up a land corridor across southern Ukraine. A Russian missile has reportedly struck an art school where 400 people were sheltering.
There are unverified reports that residents are being forcibly and illegally taken to Russia.
Authorities say thousands of Mariupol residents have been rounded up and deported to Russia, without their passports.
Those details are also sketchy.
President Volodymyr Zelensky was damning in his criticism of Russia's siege.
The UN Human Rights Office says 902 Ukraine civilians have officially been killed during Russia's invasion although it admits the actual number is probably much higher.
The number of Ukrainians forced to flee their homes has grown to about 10 million - about a quarter of the population. Humanitarian aid organisation UNICEF says the situation in Mariupol has become desperate.
UNICEF emergencies specialist Joe English spoke to Susie Ferguson from Lviv.