ROME -- Twenty-five African migrants trying to reach Italy from Libya died in the hold of a rickety boat so packed with people that the migrants could not get out as they struggled to breathe, officials said Monday after the bodies were found below decks.

Hundreds of migrants fleeing unrest and conflict in Libya and across North Africa are believed to have died since the beginning of the year in desperate journeys across the Mediterranean.

The 50-foot boat was carrying 296 people, including women and children, said Coast Guard Capt. Antonio Morana.

Some of them were stowed away in the hold, which also served as an engine room, according to the ANSA news agency.

As the air became unbreathable from exhaust fumes, migrants tried to exit but the boat was too packed for those standing above to move aside.

"From what they told us upon arrival, there was no air to breathe, apparently they were so crammed there was nowhere to go," Laura Boldrini, spokeswoman in Italy for the UN High Commissioner for Refugees, told The Associated Press.

At least some of the migrants may have died from asphyxiation, Boldrini said.

She added that the desperate conditions apparently also led to tension and possible scuffles on board as people struggled to survive.

However, she stressed that an investigation currently under way in the nearby city of Agrigento was necessary to ascertain what happened.

The officials found the corpses -- all young men -- after boarding the boat just a few miles off Lampedusa, the small island closer to North Africa than the Italian mainland.

One photo posted on Italian newspapers showed the lifeless body of a man being pulled out of the boat by mask-wearing rescuers.

ANSA said the immigrants had been at the center for several months and were protesting lack of progress in processing their requests for asylum.

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