(CNN) -- A central Syrian opposition group named a new leader Sunday and vowed new efforts to end the regime of President Bashar al-Assad.
Abdul Basit Sieda, a Syrian native now living in Sweden, is a minority Kurdish activist. His election to the helm of the Syrian National Council is widely viewed as an attempt to unite various ethnic factions.
At a news conference, he called on officials in Syria, Russia, and China "to think carefully about the situation now because the whole stability of region, if not the whole stability of the world, is at stake here. We would like to call upon them to support the Syrian people."
Russia and China have blocked U.N. Security Council resolutions that many other nations said could have pushed al-Assad to halt the killing. The two countries, which have major trade ties with Syria, said they want more balanced resolutions that call for a cessation of violence on all sides.
Sieda also called on Iran "to admit the situation on the ground and respect the will of Syrians" and to prepare "for new relations with the Syrian people based on the full interest of the Syrian and Iranian people."
A recent draft U.N. report accused Iran of exporting arms to Syria in violation of a ban on weapons sales, a Western diplomat told CNN last month. Some analysts say Iran has continued to arm Syria in its brutal crackdown on the opposition.
Sieda vowed his country will be "a free democratic state."
When asked how he planned to bridge a gap between the Syrian opposition in exile and the opposition inside the country, Sieda said, "We are in direct communication and contact with revolutionary forces inside. We are always communicating with them." He vowed to "do everything necessary to bridge that gap," but also insisted the gap was just a rumor.
"The relationship between us and the forces inside has never been stronger," he insisted.
While he railed against the violence committed by al-Assad's regime, the regime itself announced a new stage in its argument that "armed terrorist groups" are actually responsible for the violence in the country.
A "documentary" shown on Syrian state-run TV revealed "that terrorists of various nationalities from the terrorist organization Jabhet al-Nasra, which is affiliated with al Qaeda, planned and carried out" bombings in Damascus on March 8. The cars used in the attack were driven by a Jordanian terrorist and a Syrian Palestinian, "and were trailed by an Iraqi," state-run news agency SANA reported.
Jabhet al-Nasr is also known as the al Nusra Front.
SANA also said 22 "army, law enforcement and civilian martyrs" were buried Sunday.
The opposition Local Coordination Committees of Syria (LCC) said 53 people were killed Sunday, including 26 in Homs.
Among the dead was citizen journalist Khaled Bakr, founder of the Baba Amr media center, the LCC said. Baba Amr, a besieged neighborhood of Homs, came under weeks of incessant shelling by the Syrian regime earlier this year, opposition activists have said.
Also in Homs, an entire battalion, part of Syria's air defense, defected and joined the opposition Free Syrian Army, the LCC said.
At a mosque in Maarat al-Numan, part of Idlib province, El Mundo correspondent Javier Espinosa said he saw six bodies destroyed beyond recognition. "They were in pieces," he told CNN.
Separately, there were three people dead inside homes being mourned.
Residents said people were leaving a mosque when a rocket hit in the middle of the street, hitting no one. As residents gathered after to assess the impact, a second rocket hit.
The rocket had Russian markings on the shell, Espinosa said.
He described a siege in Maarat al-Numan similar to one he had previously witnessed in Homs.
It was not immediately clear what effect the SNC's new leadership will have on Syrian opposition efforts.
"The SNC is still an incomplete opposition bloc. It does represent various factions, but not everyone on the ground," said analyst Taufiq Rahim, a Dubai-based political analyst.
"The election of a Kurdish activist like Sieda may send a signal to the other factions that the SNC is trying to consolidate the Kurdish support for the council, but I don't believe that either the ethnicity or the minority factor really matters at this point. What matters is taking real action on the ground and moving forward."
Dozens of countries have recognized the SNC as a legitimate representative of the Syrian opposition, though many members of the group's leadership are expatriates.
Al-Assad has said he will not deal with opposition members influenced from the outside.
Russian Foreign Minister Sergey Lavrov said Saturday there was no alternative to U.N.-Arab League special envoy Kofi Annan's peace plan, despite mounting evidence that it's being violated daily.
"The situation looks more and more grim," Lavrov said. "For the first time since the beginning of this crisis, we see the question of foreign intervention. And our position remains unchanged. We will never agree to sanction the use of force in the U.N. Security Council."
He called foreign intervention a "dangerous game" and said it would have serious consequences in the entire region. He also blamed recent violence -- including reports of horrific massacres in Houla and Qubeir -- in part to opposition groups being supported by other nations.
Russia, along with China and four central Asian nations, has signed a joint declaration rejecting armed intervention in Syria and reiterating support for Annan's peace plan.
Amid the international talks, a humanitarian crisis looms within Syria, opposition groups say.
"Several doctors have been detained to prevent them from aiding the wounded amid a state of panic among residents due to the abuses regime forces are committing against the people there," the LCC said.
A doctor in the besieged city of Al Qusayr, near the Lebanese border, said he has to keep moving his makeshift hospital to prevent attack. Journalist Robert King documented the chaos in the hospital on video as medical staff rushed to save lives.
King said he has seen snipers targeting children.
CNN cannot independently confirm reports of casualties or violence in Syria, as the government has restricted access by international journalists.
CNN's Josh Levs, Saad Abedine, Holly Yan, and Ivan Watson contributed to this report.