Erdogan in Brussels for refugee talks with EU
Tens of thousands of refugees and migrants have been trying to find a way through the land border from Turkey after Ankara announced late last month it would no longer prevent people from trying to cross into the European Union.
"Hey Greece! I appeal to you... open the gates as well and be free of this burden," he said, adding: "Let them go to other European countries."
EU considers resettling child refugees from squalid camps
Early on Monday, Germany said the EU was considering taking in up to 1,500 migrant children who are currently housed in Greek camps.
Concern over the plight of the minors have grown as they either require urgent medical treatment or are unaccompanied by adults.
"A humanitarian solution is being negotiated at the European level for a 'coalition of the willing' to take in these children," the German governemnt said in a statement.
Berlin was ready to take in an "appropriate" share, it added, saying the country wanted to support Greece in the "difficult" situation it is facing.
Around 38,000 asylum seekers are housed in overstretched refugee centres in Greece, many in abysmal conditions.
Over 1,700 migrants have landed on Lesbos and four other Aegean islands from Turkey since Erdogan declared the borders open. Athens has since announced it will build two camps to house the new arrivals.
On Friday, Erdogan ordered the Turkish coastguard to prevent migrants from undertaking the risky Aegean sea crossing.
The coastguard however said Turkey's policy of allowing migrants and refugees to leave by land was untouched, and the instruction only affected sea crossings.
The Turkish president will meet European Council President Charles Michel and European Commission President Ursula von der Leyen at 6pm (5pm GMT) on Monday.
They will "discuss EU-Turkey matters, including migration, security, stability in the region and the crisis in Syria", Michel's spokesman said on Twitter.
"I hope I will return from Belgium with different outcomes," Erdogan said at a speech in Istanbul on Sunday as he announced the meeting.
In 2016, Turkey and the EU agreed a deal whereby Brussels would provide billions of euros in aid in exchange for Turkish authorities curbing the flow of migrants.
But Ankara has repeatedly accused the bloc of not fulfilling its promises, such as visa liberalisation measures.
Erdogan's top press aide has said one of the unmet conditions was that the EU would take in refugees from Turkey. Ankara has also repeatedly accused the EU of failing to dish out the full sum promised under the deal.
EU foreign policy chief Josep Borrell and Michel met Erdogan in Ankara on Wednesday as Turkey demanded greater support over the conflict and migrants.