- NEW: At least 117 people are killed across Syria on Sunday, opposition activists say
- Opposition: A barrel bomb flattens a residential block in Aleppo
- The Syrian government says it kills numerous "terrorists" in Aleppo
- Russia says U.S. sanctions against Syria are hurting its business
(CNN) -- The gruesome civil war in Syria has terrorized residents and left world leaders scrambling to stop the carnage that mounts daily.
Here are the latest developments in the spiraling 18-month crisis:
On the ground: Explosions, casualties
A bomb landed on a kindergarten in Aleppo, leveling a residential block and causing a "great number" of casualties, the opposition Local Coordination Committees of Syria said Sunday.
The opposition activist group described it as a barrel bomb attack, saying regime forces been dropping barrels full of TNT, nails, and fuel onto civilian areas.
Syrian state-run media, meanwhile, said regime forces killed numerous "terrorists" in Aleppo.
For over a year, the Syrian government has refused to acknowledge the popular uprising against President Bashar al-Assad's rule and has blamed "armed terrorist groups" for fueling the bloodshed.
Across the country, at least 117 people were killed Sunday, opposition activists said.
Diplomatic front: New envoy to Syria to work with Arab leaders
International envoy Lakhdar Brahimi is set to arrive in Cairo on Sunday to meet with Arab League officials on the Syrian crisis.
This is Brahimi's first such meeting since becoming the U.N.-Arab League special envoy to Syria. He faces the daunting task of trying to help stop the bloodshed in the war-torn country.
The United Nations says more than 18,000 people -- mostly civilians -- have been killed in Syria since March 2011. Opposition activists put the toll much higher, at more than 24,000 people.
Jouejati, an LCC spokeswoman, said Sunday that the situation should be classified as "genocide."
CNN cannot independently verify death tolls because the Syrian government has severely restricted access to the country by foreign journalists.
Russia: Sanctions against Syria hurt Russian business
Russian Foreign Minister Sergey Lavrov said U.S. sanctions on Syria and Iran are harming Russian business interests.
"The unilateral American sanctions against Syria and Iran are increasingly becoming extraterritorial in nature and are directly affecting the interests of Russian business, in particular banks," Lavrov said Saturday, according to the state news agency RIA Novosti.
The United States and other western countries have sharply criticized Russia, accusing it of defending the Syrian regime over financial interests and thereby allowing the regime's bloody crackdown on dissidents to continue.
Russia, along with China, has repeatedly vetoed attempts at the U.N. Security Council to take tougher action against the Syrian government.
But Russia will push the Security Council to endorse a peace plan that would set up a transitional government in Syria, RIA Novosti reported.
World leaders agreed on the plan in Geneva this year. But while U.S. and British leaders said they don't foresee al-Assad in the transitional government, Russia said the Geneva plan "did not imply that Assad should step down," RIA Novosti said.
U.S. politician says his country needs to take further action
U.S. Sen. John McCain blasted President Barack Obama for not doing more to back the Syrian opposition, calling his administration's actions thus far "shameful."
The Arizona Republican said the United States should get opposition fighters weapons "so it's a fair fight" and establish a "sanctuary or free zone" from which the opposition can operate.
He said he is not asking that U.S. troops be sent into Syria to battle government forces.
McCain, the ranking member of the U.S. Senate Armed Services Committee, said a lack of international action to date has contributed to the "rise of extremists, rise of al Qaeda, (and a) greater threat of chemical weapons."
"We've sat still and watched this massacre go on now (with) over 20,000 people (killed)," he told CNN Saturday. "How many have to die before we act?"
CNN's Hamdi Alkhshali contributed to this report.
