Pres. Komorowski after a meeting of Poland's National Security Council on Monday: photo - PAP/Jacek Turczyk
In a telephone call on Sunday, Bronislaw Komorowski said Barack Obama assured him "unequivocally as to Poland's security, knowing that Poland is not only a neighbour of Ukraine but Russia as well."
Trying to solve disputes through military means, as Russia is doing in Crimea, "raises huge doubts and concern for the future," President Komorowski said after the National Security Council meeting, which brings together Poland’s prime minister, foreign and defence ministers and leaders of opposition parties.
Komorowski said he had instructed Foreign Minister Radoslaw Sikorski to request NATO consultations under Article 4 of the alliance's founding treaty, which comes into force when the territorial integrity, political independence or security of any member state is threatened.
On possible sanctions by the EU against Russia, Komorowski said that Poland will be calling for the threat of tough measures against Moscow.
"Poland should present the case for a very firm stance on sanctions, both political and economic," Komorowski said.
US secretary of state John Kerry has muted the idea of asset freezes and other sanctions against the Russian government.
EU foreign ministers are meeting on Monday to discuss a response to the crisis.
A draft of the statement EU ministers will make, seen by Reuters, uses the phrase "strong condemnation" and calls on Russia to immediately withdraw its troops to base.
Language on "targeted measures" against Russia remains in brackets, however, meaning it has not yet been agreed by all member states.
The crisis has spread from Crimea, where Russian troops are in control, to other cities in eastern Ukraine.
On Monday afternoon, at least 100 demonstrators waving Russian flags stormed into the regional administration building in Donetsk and occupied at least one floor of the building.
The 11-storey building has been flying the Russian flag, rather than the Ukrainian flag, for three days, Reuters reports.
Russia's foreign minister Sergie Lavrov said in Geneva on Monday that Russian troops were needed in Ukraine "until the normalisation of the political situation".
Russia's parliament authorised the use of troops on Saturday, in the wake of the ousting of pro-Russian President Viktor Yanukovych last month. (pg)