At least 30 people are belived to have drowned in the Mediterranean Sea due to "non-assistance" by the Italian authorities, a monitoring organisation has alleged.
In the early hours of 11 March, Alarm Phone, a rescue hotline for migrants, claimed it alerted the Italian Maritime Rescue Coordination Centre (MRCC) -- alongside the Maltese and Lybian coastguard -- to a boat in distress, carrying 47 people.
However, despite repeated alerts, it accused them of deliberately delaying the rescue, with "only merchant vessels" reaching the scene "after many hours" -- by which point the boat had sunk.
The Italian Coast Guard said the capsizing happened outside Italy's area of responsibility, plus the rescue effort was hampered by bad weather.
"The situation was critical. The boat was adrift. The weather conditions were extremely dangerous. The people on board were screaming on the phone that they needed help," Alarm Phone wrote in a statement released on Sunday.
"Clearly, the Italian authorities were trying to avoid that people would be brought to Italy, delaying intervention so that the so-called Libyan coastguards would arrive and forcibly return people to Libya, back to the torturous conditions they had tried to escape from."
Another organisation, Sea Watch International, also claimed Italian authorities knew about the stranded vessel for over a day.
In October, Italy's far-right Prime Minister Giorgia Meloni vowed to stop migrants crossing in boats from Africa, making reducing immigration a key part of her agenda.
Her interior minister said he may block ships from bringing rescued migrants to Italy, reviving a controversial policy from 2019.
Italy -- one of the main entry points to Europe -- is currently grappling with migrant arrivals numbers.
From January to August last year, 44,000 migrants and refugees from the southern shore of the Mediterranean landed on Italy, mainly on the island of Lampedusa.
Both via email and calls, Alarm Phone claimed it "repeatedly informed" the Italian authorities about the boat in distress, sending GPS coordinates, while pointing out the "deteriorating condition" of people on board.
The alarm was first raised at 2:28 local time on 11 March, it said, calling the "systematic delay" "deadly".
The monitor's last communication with those on board was at 06:50 on 12 March, after which the boat capsized around 110 miles northwest of Benghazi, Libya.
Seventeen people were rescued by the merchant vessel Froland, while 30 others lost their lives.
The migrant boat is reported to have overturned, during the rescue operation.
During the more than 24 hours that passed between the rescue and the alarm first being raised time, Alarm Phone alleged a merchant vessel passed by the scene of distress, but did not stop.
"If instructed by MRCC Rome, it could have intervened... For many hours, the merchant vessels were merely monitoring the situation but not intervening," it added.
"For many hours, the merchant vessels were merely monitoring the situation but not intervening."
Libyan authorities were also informed about the boat in trouble by Alarm Phone, but reportedly said they could not intervene "due to a lack of assets", while emphasising that Italy was coordinating the search and rescue event.
Nine hours after the first alert, Seabird 2 of Sea Watch spotted the boat from the sky and also told the authorities the situation was urgent.
On Sunday evening, the Italian coastguard said two of those will be taken to Malta because they need urgent medical attention, while the rest will be taken to Italy.
More than 17,000 people have reached Italy so far this year, including around 4,000 this week.
"Why, given the urgency of the situation, did the Italian authorities not send adequate rescue assets immediately to the scene of distress," Alarm Phone asked in its statement.
Hundreds of people have died trying to cross the Mediterranean and reach Europe already this year, with aid workers calling it a "liquid graveyard".
Critics have blamed strict rules brought in by Meloni's far-right government for the deaths, however Italian authorities point out they have rescued thousands of migrants.
The country's coastguard said more than 1,300 migrants had been rescued recently in three separate operations off the southern tip of Italy, besides a further 200 off Sicily.
According to the UN's Missing Migrants Project, more than 26,000 migrants have either died or gone missing in the Mediterranean region since 2014.
The Italian coast guard has been approached for comment.