KASTANIES, GREECE -- Greek police fired tear gas at migrants trying to push into Greece from Turkey through the land border Monday, and a child died when a dinghy boat capsized during a sea crossing, after Turkey opened its frontier for migrants and refugees to enter Europe.

The child's death, reported by the Greek coast guard, was the first since thousands of migrants began massing at the frontiers with Greece over the weekend after Turkish President Recep Tayyip Erdogan announced an easing of restrictions on those wishing to cross to Europe.

Turkey's announcement, initially by an official on Thursday, marked a dramatic departure from a previous policy of containing the hundreds of thousands of refugees and migrants in Turkey. Erdogan apparently aims to pressure Europe into offering Turkey more support in dealing with the fallout from the Syrian war to its south.

Erdogan said Monday that Western leaders had started to call him urging him to reverse the border opening. He said he told them, "It's done, the doors are open now. You will have your share of this burden now." He added that soon "the number of people going to the border will be expressed in millions."

Thousands of migrants on Monday tried to find a way across Turkey's land border into Greece, which has made clear its borders will remain closed. Dozens managing to pass through either border fences or fording the river there. As Greek police fired tear gas, a group of several hundred holding white flags shouted "peace, peace," asking to be let into Greece. Others were trying to reach Greek islands from the Turkish coast.

Turkey's decision to ease border restrictions came amid a Russian-backed Syrian government offensive into Syria's northwestern Idlib province. That offensive has killed dozens of Turkish troops and led to a surge of nearly a million Syrian civilians fleeing toward Turkey's sealed border, threatening a dramatic new influx of displaced into a country that already hosts 3.5 million Syrian refugees.

Fighting on the ground in Idlib continued Monday, with heavy clashes between Syrian government forces and Turkish-backed fighters. Syrian troops retook the strategic town of Saraqeb, which lies on the Damascus-Aleppo highway, although violence continued nearby. The Kremlin said Erdogan and Russian President Vladimir Putin would meet in Moscow on Thursday for talks on Idlib.

The Greek coast guard said 48 migrants on a dinghy heading to the island of Lesbos, accompanied by a Turkish patrol vessel while in Turkish waters, deliberately overturned their boat once in Greek waters, triggering a rescue operation Monday morning.

The coast guard said they rescued the migrants, including two children who were hospitalized, one of them unconscious. Resuscitation efforts on the unconscious child, a boy aged around 6 or 7, failed, the coast guard said. The other child was considered out of danger. Their nationality was not immediately available.

Greek authorities said that in the 24 hours from 6 a.m. local time Sunday, they thwarted 9,877 attempts to cross the northwestern land border, either through the fence or across the Evros River, which runs along the frontier. Authorities arrested 68 people and charged them with illegal entry.

Therose Ngonda, a 40-year-old woman from Cameroon, made it into Greece by wading across the river.

Speaking in the morning, her feet still wet from the river crossing, she said she had been told migrants had 72 hours from Friday to leave Turkey. She got on one of dozens of buses and minibuses that have been ferrying people from Istanbul to the border, among about 2,000 people, including Syrians and families with young children.

Ngonda said she was put into the river on the Turkish side of the border. "They told me `go that way'."

Greece says it is faced with what has all the markings of an organized campaign by Ankara to push people through its borders. The government has sent Greek army and police reinforcements to the land border with Turkey, saying it was suspending all asylum applications for a month and would return those entering the country illegally without registering them.

The army announced a 24-hour live-fire exercise along the border for Monday, declaring the area dangerous and banning any movement of people or livestock during the exercise.

Police said migrants were concentrated at 10 parts of the border Monday morning, after a relatively quiet night. Over the weekend, Greek authorities used tear gas, water cannon and stun grenades to push back efforts by the crowd to push through the border. They also said Turkey had fired tear gas at Greek authorities on the Greek side.

Afghan university student Karimi Khalmahammad, 22, also managed to make it across. He said he had spent time inside a Taliban prison in Afghanistan and now hoped to make it to Germany.

But many of the new arrivals were being picked up by Greek authorities after crossing and were being driven away in white vans.

Greek islands near the Turkish coast also saw a major increase in arrivals from Turkey. The coast guard said that in the 24 hours until Monday morning, 977 people had reached the islands in dinghies, most of them on Lesbos but also on Chios, Samos and some of the smaller islands.

On Lesbos, local anger at the migration situation boiled over, with some residents preventing people, including young children and babies, from disembarking from a dinghy that reached a small harbour. Elsewhere on the island, they prevented buses from taking new arrivals to Lesbos' massively overcrowded migrant camp of Moria.

The new arrivals spent the night on the beach, where they remained on Monday morning. Those arriving near the island's main town of Mytilene were being taken to the island's main port for processing there in makeshift facilities instead of Moria.

Turkey's communications director, Fahrettin Altun, said Sunday the fighting in Idlib was directly linked to Turkey's decision to open the gates for refugees to Europe. He said Ankara had changed its focus to preparing for the possibility of new arrivals from Syria "instead of preventing refugees who intend to migrate to Europe."

Bulgarian Prime Minister Boyko Borissov was heading to Ankara on Monday to discuss the migrant situation with Erdogan. He said a new migrant wave would threaten stability as Europe struggles to deal with the new coronavirus.

Bulgaria has deployed additional national guard and border police on it 250-km (155-mile) long border with Turkey to stave off a possible migrant influx. Defence Minister Krasimir Karakachanov said so far there in no direct migrant pressure from Turkey but 400 troops are ready to be deployed immediately at the border in case of attempted illegal border crossings.

------

Becatoros reported from Athens. Associated Press writer Veselin Toshkov in Sofia, Bulgaria, Andrew Wilks in Ankara, Turkey and Vaggelis Papadonis in Lesbos, Greece, contributed to this report.