The EU on Wednesday said it was building a 540-million-euro  emergency stockpile of medicine and equipment to deal with chemical and nuclear emergencies as fears surge over Russia's war in Ukraine. 

The bloc's executive, the European Commission, said the supplies consist of "equipment and medicines, vaccines and other therapeutics" to treat patients exposed to chemical, biological, radiological and nuclear emergencies. 

As a first step, the EU said it was procuring "potassium iodide tablets which can be used to protect people from the harmful effects of radiation".

It said that three million iodide tablets had already been delivered to Ukraine with the help of EU members France and Spain. 

"We are taking concrete measures to increase Europe's preparedness in the face of potential threats," said EU crisis management commissioner Janez Lenarcic.

"We are setting up both a decontamination reserve and a new stockpile of equipment tailored to chemical, biological or nuclear emergencies."

The announcement comes as fears swirl over potential nuclear or chemical weapon use stemming from Russia's attack on its pro-Western neighbour. 

The West has warned that Moscow could carry out a chemical attack in Ukraine as fierce resistance from Kyiv's forces has stalled the Kremlin's advance. 

The fighting in Ukraine has also sparked worries over the safety of nuclear facilities including the Chernobyl site and Zaporizhzhia, Europe's biggest atomic power plant.

Russia has in addition placed its nuclear weapons forces on high alert as it has warned the West off directly intervening militarily in the conflict to help Ukraine.