A Ukrainian city that has served as a haven for an estimated 200,000 people who fled their hometowns has suffered back-to-back airstrikes. 

Lviv had been largely spared since the invasion began, but it was rocked by a series of powerful explosions last night. 

The governor of the region in the west of Ukraine, Maksym Kozytskyi, confirmed five people were injured. Rocket fire had also hit a fuel storage facility and factory. 

A week ago missiles struck an aircraft repair facility near the main airport and two weeks ago missiles hit a military training centre near Lviv.

The attack comes after Moscow claimed to be focusing its offensive to the country's east.

READ MORE: Foreign Editor David Pratt reports from Lviv as a Ukrainian soldier is laid to rest

An update from the UK Ministry of Defence confirmed that a majority of Russian forces "appear to be concentrating their effort to attempt the encirclement of Ukrainian forces directly facing the separatist regions in the east of the country". 

Meanwhile, the intelligence update also confirmed the situation in northern Ukraine was "largely static" as local Ukrainians fought of Russian attempts to reorganise their forces. 

The airstrikes on Lviv come as US president Joe Biden visited refugees in Poland. 

Mr Biden was in the capital, Warsaw, and far from the Ukrainian border, which is about 45 miles west of Lviv.

Lviv also has become a humanitarian staging ground for Ukraine, and the attacks could further complicate the already challenging process of sending aid to the rest of the country.

The first strike involved two Russian rockets that hit an industrial area in the northeastern outskirts of Lviv and apparently injured five people, the regional governor, Maksym Kozytskyy, said on Facebook. A thick, black plume of smoke billowed from the site for hours.

A second rocket attack occurred just outside the city hours later and caused three explosions, Mr Kozytskyy told a press briefing as another round of air raid sirens wailed. He said an oil facility and factory connected to the military, both in areas where people live, were struck on Saturday, though he did not give more details.

Mr Kozytskyy said a man was detained on suspicion of espionage at one of the explosion sites after police found that he had recorded a rocket flying toward the target and striking it.

Police also found on his telephone photos of checkpoints in the region, which Mr Kozytskyy said had been sent to two Russian telephone numbers.

The day’s events were enough to make some people in Lviv prepare to move again, said Michael Bociurkiw, a senior fellow with the Atlantic Council who was in the city.

“I saw some Kyiv cars being packed up,” he said. It was a significant turn in a week where the city had begun “roaring back” to life after weeks of war, he said.

He believes the city could remain a target, noting that Lviv was the birthplace of Ukrainian nationalism. “It’s getting closer,” he said of the war.