The situation in the Syrian rebel enclave of the Eastern Ghouta is “beyond imagination”, the UN’s co-ordinator in Syria says, following days of bombing by Syria’s government.
Panos Moumtzis told the BBC the bombardment near the capital Damascus, said to have killed at least 250 people, had caused “extreme suffering”.
The Syrian military says it is trying to liberate the area from terrorists.
Meanwhile Syrian troops have been sent to confront Turkey in the north.
The Turks have crossed the border to push back the Kurds in northern Syria.
Turkey fired shells near the advancing columns, which, it says, forced the pro-government fighters into retreat.
What’s happening in the Eastern Ghouta?
Pro-government forces – backed by Russia – intensified their efforts to retake the last major rebel stronghold on Sunday night.
One resident, Firas Abdullah, told the BBC there was nowhere to hide: “We can hear the shout and crying of women and children through their windows of their homes.
“And the missiles and the mortars are dropping on us like rain. There is nowhere to hide from this nightmare and it isn’t over.”
More than 50 children were among the dead, according to activists. About 1,200 people were injured.
The UN has called for a ceasefire to allow humanitarian aid to be delivered and the wounded to be evacuated.
The Eastern Ghouta is dominated by the Islamist faction Jaysh al-Islam. But Hayat Tahrir al-Sham, a jihadist alliance led by al-Qaeda’s former affiliate in Syria, also operates there.
- Syria country profile
New players are shifting the war
By Jeremy Bowen, BBC Middle East editor
After seven years, Syria’s war is not ending but it is changing.
President Assad now looks like he is trying to roll up this final major enclave around Damascus – the Eastern Ghouta. This would secure his victory around the capital, and would be a very big moment.
But Syria remains linked into a web of war and power politics, which guarantees more conflict.
Up in the north, there are a whole host of big powers completing for influence: Russia, Iran, Turkey and the United States. British Special Forces are there, too.
Iran is seen as a particularly big threat by the Americans, the Israelis, who are also getting involved increasingly, and the Saudis, who have been big players in the war as well.
While the cast of characters is changing, the bloodshed continues and it is certainly not over.
How bad is the situation in the enclave?
The violence in the region – designated as a de-escalation zone by Syria’s main allies, Russia and Iran, as well as Turkey – is the worst since a 2013 chemical attack, activists say.
They say at least 10 towns and villages across the Eastern Ghouta came under renewed bombardment on Tuesday.
“People have nowhere to turn,” a local doctor told the Union of Medical Care and Relief Organisations, which supports medical facilities in the Eastern Ghouta
“They are trying to survive but their hunger from the siege has weakened them significantly.”
A UN spokesperson said at least six hospitals had been hit in the area on Monday and Tuesday.
The government has allowed one humanitarian convoy into the Eastern Ghouta since late November, and there are severe shortages of food.
A bundle of bread now costs close to 22 times the national average and 12% of children under five years old are said to be acutely malnourished.
What else is going on in Syria?
On Tuesday, Syrian pro-government forces entered the Kurdish enclave of Afrin, just south of the Turkish border.
Turkey is trying to oust the Kurdish militia, which have semi-autonomous rule of the area and which have called on the Syrian military for help.
Syria has denounced the Turkish offensive as a “blatant attack” on its sovereignty, while Turkey has insisted it will not back down.
Syrian government forces, supported by Russian air strikes and Iran-backed militias, are also carrying out offensives on the north-western province of Idlib.
The UN says more than 300,000 people have been displaced by the fighting in Idlib since December.
Meanwhile, Russia’s foreign ministry acknowledged that dozens of its citizens and people from other former Soviet states had been killed or wounded in a recent battle.
It gave no details, but it is believed to be a reference to an incident in the eastern province of Deir al-Zour on 7 February, when the US military said it had killed an estimated 100 pro-Syrian government fighters in response to an attack on an allied, Kurdish-led militia force battling Islamic State militants in the area.
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