Poland is weighing greater involvement in NATO's nuclear deterrent, although would stop short of hosting nuclear weapons on Polish soil, according to a top security advisor.
"Poland would potentially be ready to increase its involvement and cooperation in the framework of NATO nuclear deterrence and assume responsibilities - but deployment of nuclear weapons is something different," said Jacek Siewiera, the security advisor to Polish President Andrzej Duda, in an interview with dpa.
The comments come days after Russian President Vladimir Putin announced plans to station nuclear weapons in Belarus, which shares a border with Poland.
The US has deployed nuclear weapons in several European countries, including Germany, for decades.
Although details are classified, it is believed that as many as 20 nuclear bombs are stored at the Büchel air base in western Germany. The weapons could be deployed by Tornado fighter jets stationed there in an emergency.
The stationing of US nuclear weapons in allied countries is known in NATO jargon as "nuclear sharing."
When asked whether he wants Poland to have nuclear weapons on its territory to feel safer, Siewiera said, "It's not about feelings, it's about the calculations. There are plenty of American nuclear weapons within Europe in a nuclear sharing programme."
But, he added, it would be "even easier to operate tactical nuclear weapons with modern equipment, with modern aircraft."
Poland's involvement in nuclear sharing has so far been limited to consultations such as taking part in top-secret meetings of NATO's nuclear planning group.
Duda, the Polish president, expressed his interest in October last year in greater Polish participation in NATO nuclear deterrence.
At the time, Duda's comments were taken to mean he was open to potentially stationing of nuclear weapons on Polish territory.
In addition to Germany, US nuclear weapons are also reportedly stationed in the Netherlands, Belgium, Italy and Turkey, although limited information is available. Experts suggest that around 100 US nuclear weapons are stationed in European countries in total.
They have an explosive force of up to 50 kilotons, which amounts to about 13 times that of the first US atomic bomb, which almost completely destroyed the Japanese city of Hiroshima in 1945.
Two other NATO countries, Britain and France, have their own nuclear weapons.
A NATO summit is due to be held in the Lithuanian capital of Vilnius in July, where the future of NATO's nuclear deterrence may be discussed in greater detail.
The Baltic states have so far not asked for any nuclear weapons to be moved eastwards.
Latvia and Lithuania, which, along with Belarus, also have a land border with Russia, instead want to push for new sanctions.
The planned Russian nuclear weapons stationing in Belarus is nothing new and poses no greater threat than Russia as a whole, said Latvian NATO Ambassador Edgars Skuja on Latvian radio.
Lithuanian Defence Minister Arvydas Anusauskas echoed these statements, saying there was no urgent need to react to Russia's plans. "The defence of a NATO country against the threat of nuclear weapons is guaranteed, whether those weapons are stationed west of our borders, east or north," he said.
He was alluding to the fact that nuclear weapons could also be in the Russian exclave of Kaliningrad to the east of Lithuania or in the St Petersburg area to the north.
A few years ago, Russia stationed Iskander missiles in Kaliningrad, which can be equipped with nuclear warheads and have a range of 500 kilometres, meaning they could fly as far as Germany.
The head of the Lithuanian army, Valdemaras Rupšys, said it is "not unexpected" that such missiles, together with converted aircraft capable of carrying tactical nuclear weapons, are now to be transferred to Belarus. He added that Lithuania does not currently have the capabilities to store nuclear weapons.
