A distress call about a migrant boat sinking in the Mediterranean Sea with 300 people on board has been made to authorities in Rome.
The International Organisation for Migration said the caller reported about 20 deaths and said another two boats were also in need of help.
It comes after at least three people, including a child, died after a wooden boat carrying dozens of migrants from the Turkish shore ran aground off the Greek island of Rhodes.
The Coast Guard said at least 83 people were on the boat. Twenty-three people were transported to a hospital for first aid treatment and the others were taken to the local police station. It was unclear what the total number of people on board was, and authorities say a search and rescue operation is ongoing in the area to locate more potential survivors.
The nationalities of the migrants was not immediately known. Tens of thousands of migrants attempt to enter the European Union through Greece each year.
Video footage and photos of the grounding of the migrant boat show a large, wooden double-masted boat with people packed on board, just metres away from the island. The vessel rocks wildly in the waves and passengers are seen in a photo jumping into the sea and swimming towards the land.
In another video, about a dozen migrants sit on a floating piece of wreckage pushed toward the shore. Coast Guard officers and passers-by jump into the waves to rescue the migrants, including a young child wearing a life-jacket.
An international aid agency spokeswoman has compared the scale of deaths in recent shipwrecks to the death toll in the sinking of the Titanic luxury liner more than a century ago.
Sarah Tyler, a spokeswoman for Save the Children in Catania, Sicily, said more than 1,000 people have died in the waters of the Mediterranean, adding "that is almost as many as died in the Titanic, and 31 times the number who died when the Costa Concordia sank."
One survivor's account has put at up to 950 the number of people on board the smuggler's boat that sank off the coast of Libya this weekend, with only a handful rescued. Last week more than 400 people died or went missing in another shipwreck.
The Bangladeshi survivor said many of the passengers were below deck and trapped inside when the boat sank.
European Union president Latvia is calling on the EU's executive arm to urgently propose new measures to beef up Europe's border agency to respond to the migrant emergency in the Mediterranean.
Latvian Interior Minister Rihards Kozlovskis said the presidency "is committed to facilitate swift adoption of short-term emergency measures once they are proposed".
Rescuers are combing the waters of the Mediterranean off Libya where hundreds of migrants are thought to have drowned when their boat overturned.
EU foreign and interior ministers are to hold emergency talks in Luxembourg.
EU foreign policy chief Federica Mogherini said the ministers would discuss whether the 28 EU leaders should hold an emergency summit this week.