Updated

The Syrian government has agreed "in principle" to attend a conference proposed by Russia and the United States on ending the country's civil war, Russia's Foreign Ministry said Friday, the first confirmation that President Bashar Assad's regime would be willing to take part in the talks with the opposition.

Despite the announcement from Moscow, one of Assad's staunchest allies, Damascus has not issued a definitive statement of its own on the proposed talks.

Russia and the U.S. joined efforts earlier this month to convene an international conference to bring representatives of Assad's regime and the opposition to the negotiating table. The aim of the talks would be to establish the outlines of a transitional government as a way out of the crisis.

More than 70,000 people have been killed and several million displaced since the uprising against Assad erupted in March 2011 and escalated into a civil war.

The main opposition Syrian National Coalition has not yet said whether it will attend the conference in Geneva, expected within two weeks, and is currently discussing its position at a gathering in the Turkish capital Istanbul. But members have said they want guarantees that Assad's departure is foremost on the agenda.

The U.S.-Russia plan, similar to the one set out last year in Geneva, calls for talks on a transitional government and an open-ended cease-fire. Washington, along with key European and Arab supporters of Syria's opposition, said Wednesday that Assad must relinquish power at the start of a transition period. Russia, however, has not committed to Assad's departure and the Syrian leader has said he will not step down before his term ends next year.

The Moscow announcement Friday came after days of talks there between Syria's Deputy Foreign Minister Faysal Mekdad and Russian officials.

Russia's Foreign Ministry spokesman Alexander Lukashevich said in televised remarks that the Syrian government has "agreed in principle" to participate in the conference.

"We note with satisfaction that we have received an agreement in principle from the Syrian government in Damascus to participate in the international conference, in the interest of Syrians themselves, to find a political solution," Lukashevich said.

But he said it is impossible to set the date for the conference at this point because there is "no clarity about who will speak on behalf of the opposition and what powers they will have."

Lukashevich also said Moscow "was not encouraged" by the results of recent meetings of members of the Syrian National Coalition.

In the Syrian capital of Damascus, legislator Sharif Shehadeh confirmed the government intends to attend, though no official statement has been issued yet. "The expectations and the opinion within the Syrian leadership is that it will most definitely attend the conference," Shehadeh told The Associated Press.

He said there should be no preconditions by the opposition or the regime because "if we start off with preconditions, we will end up in failure and this is something Russia is making clear to the opposition."

"The success of the conference lies with the opposition, not the government," he said.

At the Syrian National Coalition's three-day gathering in Istanbul, an opposition figure expressed doubts over Moscow's announcement, questioning why Damascus has said nothing.

"We are very supportive of the (U.S.-Russian) initiative. Our fear is that the regime is not going to negotiate in good faith. We would like to hear enough (from Damascus) to know that they are serious about these negotiations," said Louay Safi.

U.S. Secretary of State John Kerry on Thursday acknowledged the difficulties of launching peace talks. "Nobody has any illusions about how difficult, complicated, what a steep climb that is," he said during a visit to Israel.

Fighting continued across Syria on Friday, and state media reported that rebels fired mortar shells at the central prison in the embattled northern city of Aleppo, killing and wounding several inmates.

The pro-opposition Aleppo Media Center said clashes were underway between rebels and government troops at the prison, where a large fire had broken out. State-TV reported later Friday that troops repelled the attack on the jail and killed several gunmen.

A week earlier, Assad's forces repelled a rebel raid on the prison aiming to free hundreds of political prisoners.

The Britain-based Syrian Observatory for Human Rights said intense fighting also continued in the western Syrian town of Qusair, near the border with Lebanon.

Government forces have been trying to recapture the town since Sunday. State-run news agency SANA said troops killed a "large number" of rebels in the latest clashes.

The Beirut-based Al-Mayadeen TV, which has several reporters embedded with Syrian troops in Qusair, said government forces are advancing inside the nearby town of Hamdiyeh in an attempt to cut the rebels' last supply line.

In neighboring Lebanon, Lebanese supporters and opponents of Assad fought overnight in some of the worst fighting in the port city of Tripoli in years. Security officials said the death toll since Sunday reached 25, including three soldiers.

The officials, who spoke on condition of anonymity in line with regulations, said 200 people were wounded in the fighting. The city was quiet during the day Friday apart from sporadic shooting.