What you need to know about Syria today

Editor's note: Read a version of this story in Arabic

(CNN) -- More than 20,000 people -- most of them civilians -- have been killed in Syria's 18-month crisis. The violence continued unabated Wednesday with fierce attacks reported across the country.

Here are the latest developments in the Syrian civil war:

On the ground: The battle for Aleppo intensifies

The Syrian regime touted gains on Wednesday in the quest to control Syria's largest city and commercial hub, Aleppo:

"Units from our heroic Syrian armed forces are in confrontations with terrorist armed groups" in Aleppo, "inflicting upon them heavy losses in their numbers and equipment," state-run TV reported.

Regime and rebel fighters have battled for months in Aleppo, where civilians routinely dodge snipers and attacks from the air.

On Tuesday, regime forces shelled a bakery in nearby Marea, causing more than a dozen casualties, opposition activists said.

Government forces have previously attacked bread lines in Aleppo province, according to human rights groups and U.N. officials. Residents in opposition-friendly areas often wait in lines at night to avoid being targeted by government aircraft.

Across the country, at least 172 people were killed in fresh violence on Wednesday, the opposition Local Coordination Committees of Syria said. Sixty-seven of the deaths occurred in Aleppo, it said.

World reaction: European official says the world is at a "deadlock" on Syria

The European Union is preparing additional funds to support relief through education, food and water, EU foreign affairs chief Catherine Ashton said.

"We face a dangerous stalemate," she said Tuesday in a statement. "The truth is that, despite all the efforts, the international community is in a sense at a deadlock ... the U.N. Security Council has not been able to agree on a common response that could open the way for a political solution."

Humanitarian crisis: 1 in 4 Homs residents are in urgent need of aid

Some 550,000 of the 2.2 million people in Homs province need humanitarian aid, World Health Organization spokesman Tarik Jasarevic said after a U.N. mission composed of health experts visited the embattled province last week.

"The urgency of scaling up delivery of humanitarian aid is exacerbated by the approaching winter," he said.

About half of the province's physicians have left, and only about three surgeons remain, he said. Many of the medical facilities across the province have been damaged or destroyed, leaving the few remaining hospitals overwhelmed with patients and short on medicine and supplies.

CNN's Saad Abedine and Holly Yan contributed to this report.