British Prime Minister Rishi Sunak on Monday vowed to do “whatever it takes” to keep his country safe, amid mounting fears that suspected Chinese spy balloons could also target the UK, a day after the US military shot down a fourth flying object over the American airspace.

During a hospital visit in northern England, Sunak said the UK was in constant contact with its allies across the Atlantic and remained in readiness for any safety response.

Sunak's response comes as his defence minister Ben Wallace confirmed the UK is launching a review into the security implications of the recent incursions into western airspace.

"I want people to know that we will do whatever it takes to keep the country safe,” Sunak told reporters.

"We have something called the quick reaction alert force, which involves Typhoon planes kept on 24/7 readiness to police our airspace. I can't obviously comment in detail on national security matters but we are in constant touch with our allies and as I said we will do whatever it takes to keep the country safe," he said.

On Sunday, the US military shot down its fourth flying object, indicating that they were still trying to determine the details and did not yet rule out any explanation for the objects.

“The UK and her allies will review what these airspace intrusions mean for our security. This development is another sign of how the global threat picture is changing for the worse,” said UK Defence Secretary Wallace.

Tensions were rising since a suspected Chinese spy balloon was shot down off the coast of South Carolina last week.

According to reports, US officials fear it was sent by Beijing to monitor sensitive sites but China has described it as a weather balloon.

In the UK, Transport Minister Richard Holden said it was “possible” that Chinese spy balloons had already been sent to this country.

“It is also possible, and I would think likely, that there would be people from the Chinese government trying to act as a hostile state. I think we have to be realistic about the threat these countries pose to the UK,” Holden told ‘Sky News’.

Meanwhile, the diplomatic row continues to escalate as the Chinese foreign ministry claimed on Monday that the US has flown balloons into its airspace more than 10 times over the past year.

"It's not uncommon as well for the US to illegally enter the airspace of other countries," said foreign ministry spokesperson Wang Wenbin at a press briefing.

"Since last year alone, US balloons have illegally flown above China more than 10 times without any approval from Chinese authorities.

The first thing the US side should do is start with a clean slate, undergo some self-reflection, instead of smearing and accusing China," he said.

Washington is yet to respond to the allegations from Beijing.

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