"Three people were killed, including a female child, in yesterday's attack on a children's and maternity hospital in Ukraine's besieged Mariupol, according to updated figures this morning," the city council said on its Telegram channel. 

Officials had previously given a toll of 17 injured, including doctors, in the attack.

"The Russian forces are destroying Mariupol's civilian population deliberately and without mercy," the city council said, quoted by AFP.

It says 1,200 inhabitants have been killed in nine days of Russian siege.

The attack on the children's hospital, described by Ukrainian President Volodymyr Zelensky as a "war crime", has triggered international indignation. 

Save the Children's Eastern Europe Director, Irina Saghoyan, said in a statement on Thursday: "It's horrifying that a place people seek for help has become one of absolute and utter destruction. 

"Where can families and children turn to if even hospitals are not safe? They must not become the battlefields where conflicts rage and innocent children are the casualties."

British Prime Minister Boris Johnson said on Wednesday there were few things more depraved than the targeting of vulnerable and defenceless people, after Ukraine accused Russia of bombing a children's hospital in the port city of Mariupol.

"There are few things more depraved than targeting the vulnerable and defenceless," Johnson said on Twitter.

"The UK is exploring more support for Ukraine to defend against airstrikes and we will hold Putin to account for his terrible crimes."