Prime Minister Joseph Muscat last night was taken to hospital suffering from pain in both eyes.

The Department of Information said that he was given treatment and sent home after four hours.

Doctors ordered a few days of rest, the DOI said.

Another 32 persons present for the political activity in Zurrieq suffered from similar issues, the DOI said. The number has since grown to more than 40.

A magisterial inquiry has been opened.

Among those who also reported a burning sensation in their eyes were Tourism Minister Edward Zammit Lewis, parliamentary secretaries Chris Fearne and Michael Falzon and MP Joe Sammut.

They had been sitting behind Dr Muscat.

It is understood that the most likely cause is related to lighting and excessive UV exposure.

Both the Labour Party and the Nationalist Party have issued a statement wishing the Prime Minister a speedy recovery. The Speaker, Anglu Farrugia, also issued a statement to wish the PM well, and others who, in the same way, may have been affected.

In a note on Facebook, former parliamentary secretary Franco Mercieca, who is an ophthalmologist, told people who were in Zurrieq yesterday and who are experiencing eye discomfort to go immediately to Mater Dei Hospital. He said that speculation should stop and the police should be allowed to do their job.

Contacted by this portal, Dr Mercieca said that the source of the UV exposure is still to be established. He said it could have come from the cameras, or the lighting system or any other external source.