Il Nuovo Postiglione - Russia strikes near Polish border as Mariupol counts its dead

Russian air strikes killed 35 people at a military base outside the western city of Lviv overnight, dangerously close to the frontier with EU and NATO member Poland, local officials said.

And in the capital Kyiv, fighting raged in the suburbs, leaving a US journalist dead -- the first foreign reporter killed since Russia's invasion of its neighbour on February 24.

Meanwhile efforts continued to get help to the strategic southern port city of Mariupol, which aid agencies say is facing a humanitarian catastrophe.

A total of 2,187 residents have died in days of relentless Russian bombardment, the city council said Sunday, raising the toll by almost 1,000 since Wednesday.

Ukrainian President Volodymyr Zelensky had earlier said he hoped a humanitarian convoy accompanied by Orthodox priests would finally make it to Mariupol.

He has accused Moscow of both blocking and attacking humanitarian convoys, although he said Sunday that another 125,000 people had been evacuated that way across Ukraine.

"The key question today is Mariupol," he said, saying "we will do everything to break the resistance of the occupiers".

Talks between the two sides have yet to yield a ceasefire but Russia said Sunday that negotiators were making headway at talks in neighbouring Belarus.

"If we compare the positions of both delegations at the start of the talks and now, we see significant progress," Leonid Slutsky, a senior member of Russia's negotiating team, told state-run television network RT.

Zelensky had also said on Saturday that Russia had adopted a "fundamentally different approach" in the latest talks to end the conflict.

He told reporters it was in contrast to earlier talks at which Moscow only "issued ultimatums" and that he was "happy to have a signal from Russia".

- Broadening target sets -

For the first two weeks of the war, Russia's forces had focused on eastern and southern areas of Ukraine, but in recent days they have moved to the centre, striking the city of Dnipro.

The Lutsk and Ivano-Frankivsk military airfields in western Ukraine were hit on Friday, while overnight Saturday-Sunday, missiles struck a military training ground in Yavoriv near Lviv, about 20 kilometres (12 miles) from Poland.

Regional governor Maxim Kozitsky said 35 people were killed and 134 injured in the attack on the base, which had been a training centre for Ukrainian forces with foreign instructors, although the US said the Americans had left.

Pentagon spokesman John Kirby told ABC News that Russia was "clearly, at least from an air strike perspective... broadening their target sets".

Meanwhile in Kyiv, only the roads to the south remain open and the city is preparing to mount a "relentless defence", according to the Ukrainian presidency.

City authorities have set up checkpoints and stockpiling of food and medicine.

The northwestern suburb of Bucha is entirely held by Russian forces along with parts of Irpin, Ukrainian soldiers at the scene told AFP.

The American journalist was shot dead and another wounded Sunday in Irpin, medics and witnesses said.

Ukrainian officials were quick to blame Russian forces for the attack, which also injured a Ukrainian who was in the same car, but the exact circumstances were unclear.

Britain's defence ministry said Saturday that Russian forces were about 25 kilometres from Kyiv and that a column north of the city had dispersed, reinforcing the indication of an attempt to encircle it.

However, the Russians are encountering resistance from the Ukrainian army to both the east and west of the capital, according to AFP journalists on the spot.

Ukrainian soldiers said they believe the Russians have overestimated their resources, in terms of troops and equipment, and underestimated those of their opponents.

"They have to camp in villages in temperatures of nearly minus 10 Celsius at night. They lack provisions and have to raid houses," said one soldier, Ilya Berezenko, 27.

- 'Violence and terror' -

Zelensky has insisted the Russians will not win, saying in a video address late Saturday that "they do not have such spirit. They are holding only on violence. Only on terror".

But the conflict is taking its toll.

The UN estimates that almost 2.7 million people have fled Ukraine since the invasion, most of them to Poland, in Europe's worst refugee crisis since World War II.

Pope Francis said Mariupol had become a "martyr city", as he condemned the "unacceptable armed aggression", particularly against children.

"In the name of God I ask you, stop this massacre!" he said at the Vatican.

Attempts to evacuate hundreds of thousands of people have repeatedly failed.

"Mariupol is still surrounded... Since they cannot bring down the Ukrainian army, they target the population," a French military source said.

Turkey has asked for Russia's help in evacuating Turkish citizens from the city, Foreign Minister Mevlut Cavusoglu said Sunday.

Ukraine said on Saturday that the city's mosque -- where around 80 civilians including several Turkish citizens were sheltering -- had been fired at by Russian forces.

But Cavusoglu said that the mosque's imam "didn't confirm" the reports, telling reporters: "He said rockets and missiles had been fired on the area."

- 'Significant progress' -

Civilian casualties are high but the military toll has also been heavy.

Zelensky says the Russians have suffered "heavy losses", about 12,000 troops -- although Moscow put the number at 498, in its only toll released March 2.

About 1,300 Ukrainian troops have been killed, according to Kyiv.

Nine people were killed in a strike on the Black Sea city of Mykolaiv, a strategic hub on the road to Odessa that has been under attack for days, authorities said Sunday.

Meanwhile in the eastern Donbas region, a senior Ukrainian police officer accused Russia of using phosphorus chemical bombs around Popasna, around 100 kilometres (60 miles) west of Lugansk city.

Further south, bombs struck the Sviatoguirsk monastery, where nearly 1,000 civilians were sheltering at the weekend, wounding 30 people, a Ukrainian official said.

In the southern Ukrainian city of Kherson, local media said thousands gathered in protest at Russian control, prompting Russian troops to fire warning shots.

Zelensky continues to call for more help from Western allies.

Washington and its EU allies have sent funds and military aid to Ukraine and imposed unprecedented economic sanctions on Russia.

Washington on Friday added more layers of sanctions, this time ending normal trade relations and announcing a ban on Russian vodka, seafood and diamonds.

However, he has ruled out direct action against nuclear-armed Russia, warning that it would lead to "World War III".

burs-ar/kjm

R.Accetta--INP