As diplomats from around the world converge on New York for the U.N. General Assembly this week, the Syrian civil war — and what to do about the country’s embattled regime — will be high on the agenda.

Some of the main goals are “to increase pressure and to increase the isolation of the regime of al-Assad,” German Foreign Minister Guido Westerwelle said. Germany holds the rotating presidency of the U.N. Security Council this month.

But if history repeats itself, talks about Syria at the United Nations won’t necessarily amount to effective action at the world body.

Many countries decry what they say is the Syrian government’s cruel, violent treatment of civilians, and some have issued sanctions against the Syrian government.

Yet action at the U.N. Security Council has been muted. Countries such as the United States, France and Great Britain have tried to formally denounce Syrian President Bashar al-Assad’s regime, but Russia and China have vetoed such attempts.

The two countries say they oppose foreign intervention in Syria and want an internal political solution. But some analysts say they believe Russia and China are worried about trade ties.

As world leaders remain at an impasse on what to do about Syria, dozens or hundreds of people are reportedly killed each day in the country. Here are the latest developments in Syria’s 18-month crisis:

On the ground: Terror in Syria’s largest city

The commercial hub of Aleppo became a battlefield once again Monday, with children falling victim to incessant government attacks, opposition activists said.

At least eight people — including three children — were killed after warplanes pummeled a city neighborhood, the Local Coordination Committees of Syria said.

Several residential buildings were flattened, the opposition group said.

Across the country, at least 30 people were killed in fresh violence Monday, according to the LCC. They join more than 26,000 people who have died in Syria since March 2011, opposition activists said.

Syria, on state-run media, said its forces “cleaned” an Aleppo agricultural institute “of terrorists and seized a large amount of ammunition,” and “cleaned” some surrounding areas as well.

“An army unit eliminated all members of an armed terrorist group in a qualitative operation in al-Sukari neighborhood,” the state-run Syrian Arab News Agency reported.

The government also reported that it inflicted “heavy losses” on “terrorists” in Damascus suburbs and elsewhere.

In the capital: Dissidents call for al-Assad’s ouster

With the knowledge of Syria’s rulers, opposition figures met Sunday in the capital city of Damascus and urged “toppling the regime.”

Denouncements of the Syrian regime are nothing new among opposition groups, though it is rare for them to be made in Damascus — effectively under the government’s watch.

But one of the most prominent and vocal opposition groups, the Syrian National Council, was not represented at the meeting

Syrian state-run media acknowledged the meeting of dissidents but failed to mention the call for al-Assad’s ouster.

Conference organizers later issued a statement detailing positions agreed to by participating groups, including toppling the regime and building support for a democratic state.

The dissidents also agreed to pursue “nonviolent resistance … to accomplish the goals of the revolution” and praised Syrian troops who had refused to “kill their fellow countrymen” and defected to join the rebel Free Syrian Army.

A day before the summit began, the event’s organizer — the National Coordination Body for Democratic Change — said that three of its members were detained by Syrian air force Intelligence personnel after driving from Damascus International Airport on Thursday.

The government’s Information Ministry said the three were “kidnapped by terrorists on the airport highway,” SANA reported Friday, and warned the perpetrators of “legal repercussions.”

—CNN’s Holly Yan, Saad Abedine and Sonia Kennebeck contributed to this report.