ISLAMABAD — Pakistani Prime Minister Shehbaz Sharif declared a national day of mourning for citizens who died when the fishing trawler packed with migrants sank off the Greek coast.

As many as 750 men, women, and children from Syria, Egypt, the Palestinian territories, and Pakistan were on board the vessel, trying to reach relatives in Europe. The Greek coast guard has defended its response to the tragedy that left more than 500 migrants presumed drowned. The vessel sank on Wednesday.

Sharif expressed his grief over the tragedy and said Monday would be observed as a day of mourning, with the national flag flying at half-staff.

He previously said that Pakistan’s embassy in Athens has identified 12 nationals who were rescued by the coast guard. There was no official information on how many Pakistanis were onboard the vessel, how many survived, or how many perished.