Andrzej Duda made the appeal after holding emergency talks on the Ukraine crisis with senior government figures, top security officials and military leaders, the state PAP news agency reported.
The president told reporters that the Russian invasion, launched in the early hours of Thursday, was "an unprecedented violation of international law.”
“I believe that the international community will respond to this,” Duda stated, adding: “We’ll be in contact throughout the day with the leaders of the European Union and NATO.”
The Polish head of state told reporters: “We stand with Ukraine as its neighbour, as NATO, as the EU. We hope that the Russian aggression will be stopped.”
“We appeal for the cessation of war activities,” Duda also said, pledging he would be “doing everything to make sure that the events taking place in Ukraine are stopped.”
'Poland is safe': US ambassador
Meanwhile, the newly appointed US ambassador to Poland, Mark Brzezinski, offered assurances in a media interview that Poland was safe amid the armed conflict across its eastern border.
Speaking in an interview with private broadcaster TVN24, the envoy stated in Polish: “Poland is safe. Poland is secure. America is standing shoulder to shoulder with Poland, its NATO partner.”
He added in English: “We are ready for every contingency,” reiterating: “Poland is safe.”
Poland braces for Ukrainian refugees
Meanwhile, a Polish deputy interior minister announced on Thursday morning that the government was setting up special reception centres for Ukrainian refugees fleeing the Russian invasion.
Paweł Szefernaker said in a radio interview that eight such sites would open within hours in Poland's eastern Lubelskie and Podkarpackie provinces, which border Ukraine.
“These centres will provide refugees with food, medical assistance and information,” he said.
Polish Red Cross raising funds for Ukraine
The Polish Red Cross announced it was ready to offer various forms of support in the wake of the Russian attack, including help with the medical assessment of Ukrainian refugees arriving at the Polish border, the PAP news agency reported.
The organisation said it had already donated 370 camp beds for potential Ukrainian arrivals in the Lubelskie region, according to the news agency.
The Polish Red Cross offered to supply camp beds, sleeping bags and blankets, as well as food and hygiene products, and provide anyone injured with care and shelter, a statement read.
The organisation also said it could help organise a relief convoy, and was already collecting donations for Ukrainian refugees.
Those wishing to donate can do so at the following bank account: 16 1160 2202 0000 0002 7718 3060. Transfers should be titled: UKRAINA.
The money will be spent primarily on food and medical supplies, the Polish Red Cross said.
Russian President Vladimir Putin in the early hours of Thursday morning announced a "special military operation" against Ukraine to eliminate what he said was a serious threat against his country, the Reuters news agency reported.
Top Polish officials on Thursday condemned Russia's attack on Ukraine and vowed to support the Ukrainian people.
(pm/gs)
Source: IAR, PAP
Click on the audio player above for a report by Radio Poland's Elżbieta Krajewska.