* Government says Libyan forces took boat, others see piracy

* Migrant arrivals continue as spring weather helps sailing

* Dozens rescued with horrific burns as crisis continues

* Four European officials calls for coordinated response (Adds European Affairs ministers' statement, detail)

By Antonio Denti

PALERMO, Italy April 17 (Reuters) - Italian navy personnel on Friday boarded a Sicilian fishing boat and took custody of a Libyan soldier on board after the vessel was seized overnight off the coast of the North African state, the defence ministry said.

The Mediterranean has grown increasingly deadly as hundreds of thousands of people put themselves in the hands of migrant traffickers for harrowing journeys on overloaded boats to Europe to escape conflicts in North Africa and the Middle East.

A defence ministry statement said a tugboat apparently belonging to Libyan security forces had stopped an Italian trawler early on Friday, around 90 km (55 miles) from the port of Misrata.

Italy's navy subsequently intercepted and took control of the vessel, encountering no resistance from the sole Libyan soldier on board, who was transferred to an Italian ship.

One fisherman suffered minor injuries, the ministry said.

A spokesman for a Sicilian fishing trade association had said earlier that the incident was likely the work of pirates. No such attacks have been reported before.

"This is probably an act of piracy because the tugboat that approached the trawler had no Libyan governmental insignia," the spokesman, Francesco Mezzapelle, told Reuters. He said the trawler was manned by three Italians and four Tunisians.

HARROWING CONDITIONS

Libya has descended into anarchy as two rival governments and various armed factions fight for control.

The lawlessness has helped migrant traffickers who charge thousands of dollars to mainly sub-Saharan Africans for passage across the Mediterranean to an expected better life in Europe.

Around 13,000 people have been rescued over the last week as good weather improved sailing conditions. About 1,000 people have drowned this year, an almost tenfold rise over the same period last year, according to the U.N. refugee agency (UNHCR).

Financially strapped Italy shut its Mare Nostrum search and rescue operation last year, calling for more help from the European Union. Mare Nostrum was replaced by a Europe-wide operation called Triton but rights groups have criticised it for having a smaller budget and remit than its predecessor.

The European affairs ministers of France, Germany and Slovakia joined their Italian counterpart in a statement on Friday calling for a "resolute European answer".

Those who survive the journey speak of appalling conditions.

On Friday, an Italian vessel picked up 60-70 migrants including children, many of them suffering heavy burns caused by a gas cylinder explosion before they left Libya, the UNHCR said.

Several people were killed in the blast in an area where traffickers hold migrants before loading them onto boats, and one 25-year-old woman died on the boat. Survivors were brought to the small island of Lampedusa off Sicily.

"The traffickers would not allow them to leave and reach the hospital so they didn't get treatment for a few days and then they were put on a boat," UNHCR spokeswoman Barbara Molinario said. (Additional reporting by Roberto Landucci in Rome; Writing by Isla Binnie; Editing by Mark Heinrich)