WRAPUP 12-Ukrainians defy Russian surrender demand in Mariupol on 'Easter of war'

(Adds comment by Zelenskiy, updates dateline)

* Russia tells Ukrainian fighters in steelworks to lay down arms

* Bombardments continue elsewhere around Ukraine

* Ukrainian President Zelenskiy says occupiers must pay

* Pope decries 'cruel and senseless' conflict

By Oleksandr Kozhukhar and Alessandra Prentice

LVIV/KYIV, April 17 (Reuters) - Ukrainian soldiers resisted a Russian ultimatum to lay down arms on Sunday in the pulverised port of Mariupol, which Moscow said its forces had almost completely seized in what would be its biggest prize of the nearly two-month war.

Ukrainian Prime Minister Denys Shmyhal said troops in Mariupol were still fighting despite a Russian demand to surrender by dawn.

"The city still has not fallen," he told ABC's "This Week" programme, adding that Ukrainian soldiers continue to control some parts of the southeastern Ukrainian city.

Russia said on Saturday it had control of urban areas, with some Ukrainian fighters remaining in the Azovstal steelworks overlooking the Sea of Azov.

Capturing Mariupol, the main port in the Donbas region, would be a strategic prize for Russia, connecting territory held by pro-Russian separatists in the east with the Crimea region that Moscow annexed in 2014.

After failing to overcome Ukrainian resistance in the north, the Russian military has refocused its ground offensive on Donbas while launching long-distance strikes at targets elsewhere including the capital, Kyiv.

About four million Ukrainians have fled the country, cities have been shattered and thousands have died since the start of the invasion on Feb. 24.

The economic damage is significant too - Shmyhal said Ukraine's budget deficit was around $5 billion a month and called for Western governments to provide more financial aid.

President Volodymyr Zelenskiy said on Twitter he had discussed ensuring Ukraine's financial stability and preparations for post-war reconstruction with International Monetary Fund Managing Director Kristalina Georgieva. She replied that support was "essential to lay the foundations for rebuilding a modern competitive #Ukraine."

Earlier, he posted on his Telegram account images of destruction he said were akin to World War Two.

"The occupiers will be responsible for everything they did in Ukraine," Zelenskiy said.

'CRUEL AND SENSELESS WAR'

Implicitly criticizing Russia, Pope Francis pleaded for an end to the bloodshed and lamented the "Easter of war" during his address in St. Peter's Square after Mass.

"May there be peace for war-torn Ukraine, so sorely tried by the violence and destruction of the cruel and senseless war into which it was dragged," he said.