At least three migrants were declared missing at sea, while five others were injured and treated in hospitals, health authorities in the Italian port city of Crotone said on Sunday, adding that two of them were in a serious condition.

Two police officers were injured as they tried to steer the migrant ship to safety, a police commander Emilio Fiora was reported as saying by Adnkronos news agency.

He said the ship’s engine caught fire, most likely due to a fuel leakage, and there was an explosion.

Twelve survivors were taken to a migrant reception centre in the city of Crotone, according to Italian news agency ANSA.

The migrant vessel originally had 34 people on board, but 13 migrants reached the shore before Italian authorities intervened to bring it to port, ANSA said.

Meanwhile, a boat with 450 migrants on board was rescued by the Italian coastguard off the island of Lampedusa as it risked capsizing in strong winds.

Italy is a major route into Europe for hundreds of thousands of asylum seekers and other migrants.

Numbers fell sharply after a crackdown in Libya on smugglers, but there has been a resurgence in 2020 despite Rome having closed its ports to migrant boats, saying it is impossible to help migrants due to the coronavirus crisis.

Some 18,000 migrants have reached Italy’s shores so far in 2020, compared with around 4900 in the same period in 2019.

More than 500 refugees are known to have died in the Mediterranean this year, and the real number is estimated to be considerably higher.

The surge in migrant arrivals via sea has sparked protests from politicians representing frontline areas.

On the island of Lampedusa, Italy’s southernmost point, Mayor Salvatore Martello on Sunday announced a “general strike” to protest against the latest mass arrival of sea migrants from North Africa.

“We’re on our knees,” he said.

“The situation is unbearable.

“Either the government has to take immediate decisions, or the entire island will go on strike.”

The mayor condemned the central government for “continuing to maintain a scary silence” on the situation in Lampedusa.

He called for navy boats to be used to intercept migrant vessels and transfer them out of Lampedusa since the local migrant reception centre “is full beyond all limits”.

The president of Sicily, Nello Musumeci, on Facebook urged Conte to call a cabinet meeting to tackle “the [migrant] emergency of the past months, which has become unbearable in the past hours”.

Italy’s interior ministry reacted by saying three more COVID-19 quarantine ferries – adding to the two already present – were being sent to Lampedusa to host newly-arrived migrants.

One ferry will arrive by Monday, and two more by Wednesday, the ministry said, adding that 328 migrants would be transferred from the island between late Sunday and Monday morning.