(Bloomberg) -- The Polish government has asked the UK for new air-defense support and technology to help it repel Russian missiles, drones and spy balloons, people familiar with the matter said.

The request came after a series of suspected incursions into Polish air space in recent months and heightened concern in Warsaw about spillover from Russia’s invasion of Ukraine. 

The UK’s Defense Ministry declined to comment on the request, saying only that its Sky Sabre Ground Based Air Defence system is currently deployed in Poland. The UK had previously signed a £1.9 billion ($2.4 billion) export agreement to provide Poland with ground-based air-defense capabilities. 

Britain is currently considering its response to the Polish request, a person familiar said. A spokesman for Poland’s National Security Bureau declined to comment.

The issue of Poland’s air defense moved front and center in November, when a blast killed two people in a village near Poland’s eastern border with Ukraine. Alarm over a possible Russian attack on NATO territory was defused when the military alliance and the government in Warsaw attributed the incident to Ukrainian forces trying to shoot down scores of Russian rockets. 

Russia’s Defense Ministry dismissed initial reports that its missiles had landed on Polish territory as a “deliberate provocation” aimed at escalating tensions. 

Since the incident, other incursions have added to a sense of urgency. 

Polish authorities last month launched an investigation after the wreckage of what is believed to be a Russian missile was found by a civilian near Bydgoszcz, a city northwest of Warsaw, in late April. The discovery stirred wide media attention and a public spat between military leaders and Defense Minister Mariusz Blaszczak, who complained that he hadn’t been informed. 

Polish President Andrzej Duda also said in May that authorities had detected an observation balloon in its air space that originated from Belarus. In March, Ukraine’s air force said a Russian drone entered Polish air space before being shot down in Ukrainian territory. 

The Polish request is part a surge in European defense spending in recent months. The nation’s allocation for military hardware has risen more than two-fold from last year as the government pledges to spend 4% of economic output on defense this year — a higher proportion than any NATO state before the war. 

--With assistance from Alberto Nardelli.

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