Syrian state-run television reported Thursday that forces loyal to President Bashar al-Assad killed three Westerners, including an American woman and a British national, who they claim were fighting with the rebels and were found with weapons and maps of government military facilities.

Syrian TV identified the woman, releasing what it claimed were her Michigan driver's license and U.S. passport. It also released what is said was the name and passport of a British citizen. It did not identify the third Westerner.

The TV report claimed the three were also found with a flag of the al-Nusra Front, an al Qaeda-linked group.

The United States is aware of the claim that an American was killed and is working through the Czech Republic mission in Syria to obtain more information, a State Department official, speaking on condition of anonymity, told CNN.

Citing privacy considerations, "we are unable to comment further," the official said.

[Original story published at 4:44 p.m. ET]

Both sides express doubts on Syrian peace talks

A leader of Syria's main rebel coalition said Thursday the group may not participate in an international conference aimed at brokering an end to the civil war.

"It is difficult to continue when Syrians are constantly being hammered by the Assad regime with the help of outside forces," said George Sabra, acting chairman of the National Coalition, in a statement.

He cited the siege of Qusayr and attacks on Eastern Gouta, a suburb of Damascus, as well as what he said was an "invasion" by Iranian militia members in support of President Bashar al-Assad.

Russia, which supports Damascus, expressed its own reservations. Conditions on the peace talks demanded by the National Coalition are too restrictive, Russian Foreign Minister Sergei Lavrov told reporters, state news agency ITAR-Tass reported.

"One has the impression that the National Coalition and its regional sponsors are doing their utmost in a bid to prevent the beginning of a political process and resort to all means, including brainwashing in the West, to induce military intervention," Lavrov is quoted as saying. "We regard such approaches as impermissible."

In addition, the coalition "is not the sole representative of the Syrian people," Lavrov said. "The coalition has no constructive platform."

The National Coalition has demanded that al-Assad step aside as a condition for its participation in the talks, which were originally scheduled to be held this month in Geneva, Switzerland, but have been delayed.

The Syrian government has insisted that any talks be held without preconditions and has said that al-Assad will finish his term and must be qualified to run again in the 2014 elections.

Russian, U.S. and U.N. officials are to meet next Wednesday in Geneva, the Interfax news agency reported, citing a Russian Foreign Ministry source.

No date has been announced for talks there that would include representatives of the Syrian government and rebel forces.

It has been tough to get the two sides together.

In December, Russia invited then-opposition leader Ahmed Moaz al-Khatib to talks in Moscow, but he refused to meet in a Russian venue.

Al-Khatib said Russia had overlooked atrocities in Syria and must condemn the crimes before his group could engage in talks.

But he did meet with Lavrov in February during a break in an international security conference in Munich, Germany.

Last summer, representatives from world powers that had been at odds over the Syrian conflict drew up a peace plan that called for a cease-fire, a transitional government and a new constitution, though it did not specify whether al-Assad would have to step down.

Russia and China joined France, Britain, the United States and Turkey, as well as Arab League nations, in agreeing on the plan.

Neither the Syrian government nor the rebels showed a willingness to sign on to the plan.

The comments Thursday from Lavrov and Sabra came a day after the National Coalition got a failing grade from some of its members.

"This leadership failed in all tests: organizational, political and humanitarian," said the Local Coordination Committees of Syria and other groups in a statement. "The coalition, based on its current organizational structure, is impotent to carry out the duties entrusted to them because of the negative inter-political bickering between the various groups and members."

Discussion of the talks comes as the conflict in Syria threatens to spread.

Some 3,000 to 4,000 Lebanese Hezbollah fighters have been deployed to Syria, where they are fighting alongside government forces, French Foreign Minister Laurent Fabius told the Foreign Affairs Committee of France's National Assembly.

The Lebanese fighters have been involved in a battle for Qusayr, a town of about 20,000 that sits astride one route to the Syrian coast and another to the Lebanese border.

For the rebels, holding Qusayr represents a way of limiting the regime's ability to sustain itself.

On Thursday, the media office of the Syrian Coalition in Istanbul, Turkey, said in an appeal for help that the number of wounded citizens in Qusayr had exceeded 1,000.

The state-run Syrian Arab News Agency said the fighting was part of its mission "to pursue terrorists in Qusayr and its countryside."

In an interview broadcast Thursday night by the Hezbollah television station Al-Manar, al-Assad was quoted by Lebanese media as saying, "Syria and Hezbollah are one axis."

Hezbollah forces "are in Lebanon and Syria, on the border area," al-Assad said.

According to the pro-Hezbollah Al-Akhbar newspaper, he said, "There are groups of (Hezbollah) party fighters in the border areas with Lebanon. But the Syrian army is the one fighting and running battles against the armed groups, and will continue in this battle in order to eliminate" what he described as "terrorists."

The president expressed skepticism that the talks proposed for Geneva would prove fruitful, the newspaper reported.

Al-Assad is further quoted as saying that "Syria received the first batch of the Russian S-300 missiles, anti-aircraft systems" and that "the rest of the shipment will arrive soon."

"The contracts are not related to the conflict," he said. "We negotiate with them for various kinds of weapons for years. And Russia is fulfilling these contracts."

Russia has been criticized by the West for reported sales of six S-300 air defense systems to Syria under a 2010 contract.

Moscow, however, has said such deliveries would conform with international law and has denied supplying Syria with weapons that can be used against civilians.

While some countries -- including the United States, France and Britain -- have called for al-Assad to step down, they have not agreed on whether to arm Syrian rebels.

The war has caused more than 1.6 million Syrians to flee their homeland, the Office of the U.N. High Commissioner for Refugees said Thursday.

Some 11,455 refugees registered in North Africa, 495,776 in Lebanon, 491,912 in Jordan, 377,154 in Turkey, 153,976 in Iraq and 75,442 in Egypt.

On Thursday, the aid group Medecins Sans Frontieres, also known as Doctors Without Borders, called the conditions in Jordan increasingly precarious.

"Jordanian authorities are unable to provide them with adequate water and health care," said the organization in an appeal for funds.