Poland’s leaders stressed the need for a strong defence in the face of war in neighbouring Ukraine and redress as they led solemn ceremonies to mark the 85th anniversary of German Nazi forces invading and bombing Polish territory at the start of the Second World War.

Sirens wailed and a memorial bell tolled as President Andrzej Duda and deputy ambassador of Germany Robert Rohde attended an observance on Sunday in the town of Wielun, the first civilian target of German bombing in the small hours of September 1, 1939.

Some 1,200 people were killed in the attack which witnesses say began at 4.40am.

Mr Duda said: “We can say that we have forgiven even though we remember, even though the pain is persisting and even though there are still tens of thousands of those who have been directly hurt by the Germans.”

He also called on Berlin to make amends.

Meanwhile, at a monument on the Baltic Sea’s Westerplatte peninsula, where a military outpost was shelled by a German warship just minutes after Wielun was attacked, Prime Minister Donald Tusk and defence minister Wladyslaw Kosiniak-Kamysz laid wreaths and attended a memorial roll call for fallen soldiers.

At the time, the outpost’s outnumbered troops fought for seven days before surrendering to the Germans, becoming a symbol of heroism and patriotism.

Mr Tusk said war is present again in the region as the Russian invasion of Ukraine, which began in 2022, grinds on.

In a clear reference to Germany, he said it is not enough to speak about “reconciliation” or to “bend your head in a sense of guilt”, adding the best sign of lessons learned from the past is “the readiness to organise the entire western world, Europe and Nato for the defence against aggression that we are witnessing today in the battlefields of Ukraine”.

He added: “Today we will not say ‘Never again’. Today we must say ‘Never again alone’.”

Mr Tusk also said Poland is building “the most modern army in Europe, one of the strongest in Europe” to actively contribute to the unity and strength of the Nato defence alliance and the European continent and “to defend our civilisation” and “never again expose our homeland to any risks”.

German foreign minister Annalena Baerbock posted on social media site X, saying she wishes Poles and Germans become “completely normal” towards one another, adding that was the desire of former Polish foreign minister Wladyslaw Bartoszewski, who survived the German invasion.

She also said it is their responsibility, “while bearing our past in mind”, to constantly work to keep their friendship alive.

In more than five years of the war and brutal German occupation, Poland lost six million citizens – a sixth of its population – of which three million were Jewish. The country also suffered huge losses to its infrastructure, industry and agriculture.

Poland’s previous right-wing government demanded almost £1 trillion in damages from Germany. Mr Tusk’s current cabinet has toned the demand down to some form of compensation that could serve to strengthen the ties between the two neighbours.

Germany insists the matter is closed as it had paid damages to the Moscow-led East Bloc after the war. Warsaw says it did not get any share of it.

Addressing attendees at the Wielun observance, the Polish president said: “Forgiveness and the admission of guilt is one thing, but compensation for the damage caused is another thing. And this issue has not been settled yet.”