President Bashar al-Assad said victory in Aleppo would be a "huge step" towards ending Syria's five-year civil war, ignoring pleas for a truce as rebels in the city lose more ground.
In a blistering three-week offensive, Syrian government forces have seized about 80 percent of east Aleppo, a stronghold for rebel groups since 2012, with increasingly cornered opposition factions calling for an "immediate five-day humanitarian ceasefire".
The United States, Britain and France have also called for a truce, warning of a "humanitarian catastrophe".
US Secretary of State John Kerry and his Russian counterpart Sergei Lavrov were set to meet Thursday in Germany's Hamburg after talks the previous day failed to achieve a breakthrough on efforts to halt the fighting in the devastated city.
Asked at the start of the session about Russia's position on a ceasefire, Lavrov said: "I am in agreement, and I confirm support for the American proposal of December 2", referring to a meeting with Kerry in Rome at which they were believed to have agreed on a plan to evacuate civilians and rebels from east Aleppo and to work towards a new ceasefire.
Tens of thousands of children in Aleppo are "sitting targets" in the ongoing fighting, according to Save the Children Syria Director Sonia Khush.
"It defies belief that after nearly six years of suffering through this war, the international community is still willing to stand by as civilians are bombed with seeming impunity," she added.
According to the Syrian Observatory for Human Rights, 19 civilians were killed in the regime bombardment of east Aleppo on Wednesday.
In an interview with Syrian daily Al-Watan, published Thursday, Assad said defeating the beleaguered rebels in Aleppo "will be a win for us, but let's be realistic -- it won't mean the end of the war in Syria".
"But it will be a huge step towards this end."
When asked about the possibility of a truce in Aleppo, Assad said, "it's practically non-existent, of course".
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Assad said a rebel loss in Aleppo "will mean the transformation of the course of the war across Syria" and would leave opposition factions and their backers with "no cards left to play".
Aleppo was once known as the beating heart of culture and commerce in Syria, but the outbreak of fighting there four years ago left it divided between rebels in the east and government forces in the west.
In his wide-ranging interview, Assad pledged to fight rebels even beyond Aleppo, because "the war in Syria will not end until after the complete elimination of terrorism".
"Terrorists are present elsewhere -- even if we finish with Aleppo, we will continue our war against them," he said.
- 'Only available solution' -
Assad touted local agreements between his government and rebel groups as the best way to resolve Syria's complex conflict.
Such deals have seen opposition fighters quit a string of towns around Damascus in recent months, often in exchange for an end to regime bombardment.
"It is the only available solution, in parallel with striking the terrorists. Its success has been proven over the past two to three years, and is now speeding up," Assad told Al-Watan.
He said these agreements had protected Syrian civilians and infrastructure and allowed former rebels to "return to the bosom of the state. What more could we want?"
Syria's conflict erupted in March 2011 with widespread demonstrations but has since turned into a brutal multi-front war drawing in world powers.
Many Western countries cut ties with Damascus in 2011 and have imposed crippling economic sanctions, but Assad said he remained open to better relations with them.
"We really do want ties with every country in the world, including the West, despite our previous knowledge of their hypocrisy."