A handout photo shows migrants onboard a boat during a rescue operation, before their boat capsized on the open sea, off Greece. Reuters

Every year, thousands of young Pakistanis embark on perilous journeys attempting to enter Europe illegally in search of a better life.

Local media said as many as 300 Pakistanis had died after a rusty trawler sank near Greece's Peloponnese peninsula on Wednesday.

Officials said nine people had been detained in Azad Jammu and Kashmir (AJK) — home to a majority of the victims — and one in Gujrat, a city that has long served as a springboard for migrants.

"They are presently under investigation for their involvement in facilitating the entire process," said Chaudhary Shaukat, a local official from Pakistan-administered Kashmir.

Between 400 to 750 people were believed to be aboard the boat, according to a joint statement from the International Organisation for Migration and UN Refugee Agency.

On Saturday, Pakistan's ministry of foreign affairs said 12 nationals had survived, but it had no information on how many were aboard the boat.

An immigration official told AFP on condition of anonymity that the figure could surpass 200.

Agence France-Presse