SOFIA: A Bulgarian man was in critical condition Wednesday after setting himself on fire outside the presidency, authorities said, in the fourth such case in a recent wave of protests.

The 51-year-old man was hospitalised with 25-percent burns after dousing himself with petrol and setting himself ablaze in the capital around 13:35 pm (1135 GMT), the interior ministry said.

Three other men have died after self-immolating in an upsurge of public anger since last month against poverty and corruption in the European Union's poorest country. The protests forced the resignation of the government on February 20.

A caretaker technocrat government took office on Wednesday to run the country ahead of early elections on May 12 that polls suggest will return a highly fragmented parliament.