MOSCOW (AFP) - The Syrian government said Monday it was "ready" for talks with rebels as the opposition overturned its planned boycott of a conference to conside the "next steps" in ending the deadly two-year conflict.

As diplomatic efforts to end the conflict kicked into high gear, President Bashar al-Assad's foreign minister said the authorities in Damascus were ready to talk to armed rebels.

"We are ready for dialogue with all who want dialogue, including those who are carrying arms," Walid al-Muallem said on a visit to Moscow - the first such offer by a top Syrian official.

Mr Muallem held talks with his Russian counterpart Sergei Lavrov, whose country is one of the few big powers to maintain ties with the Syrian government.

Armed rebels have battled the Assad regime since the start of an uprising against his rule in March 2011 and now control swathes of Syrian territory, especially in the north.

According to the UN, the fighting has claimed 70,000 lives.

"We still believe in a peaceful solution to the Syrian problem," said Mr Muallem, pointing to the creation of a government coalition that would negotiate with both the "external and internal opposition." Russia has renewed calls for rebels and the regime to engage in direct negotiations to end the conflict, warning that pressing for a military victory risked destroying Syria.

Reacting to Mr Muallem's offer, US Secretary of State John Kerry said on a visit to London: "It seems to me that it's pretty hard to understand how, when you see these Scuds (missiles) falling on the innocent people of Aleppo, it's possible to take their notion that they're ready to have a dialogue very seriously." The rebel Free Syrian Army's chief of staff Selim Idriss was also not convinced.

"I am not going to sit down with him (Assad) or with any other member of his clique before all the killing stops, or before the army withdraws from the cities," Mr Idriss told pan-Arab broadcaster Al-Arabiya.

Mr Kerry, who is on a nine-nation tour of US allies, managed to convince the Syrian opposition Monday to revoke its planned boycott of a Friends of Syria conference in Rome on Thursday.

Syrian National Coalition chief Ahmed Moaz al-Khatib said on his Facebook page his group would go after Kerry and Hague "promised specific aid to alleviate the suffering of our people".

The Coalition had announced on Saturday its intention to withdraw from the 11-nation meeting in Rome and cancel planned visits to Washington and Moscow in protest at the "international silence" over "crimes committed against the Syrian people." But Mr Kerry urged the opposition Monday to reconsider.

"I want our friends in the Syrian opposition council to know that we are not coming to Rome simply to talk. We are coming to Rome to make a decision on next steps," Mr Kerry said after talks with his British counterpart William Hague in London.

And he said the killings in the Syrian city of Aleppo last week were "further evidence" that President Bashar al-Assad must stand down.

"The Syrian people deserve better than the horrific violence that now invades and threatens their everyday lives," Mr Kerry said.

Hague also expressed "frustration" at the situation and said: "There has been no sign of a political and diplomatic breakthrough." "In the face of such murder and threat of instability, our policy cannot remain static as the weeks go by, and it is an important opportunity in Rome on Thursday to discuss this with our allies and partners," he said.

Britain wants to provide more support for the Syrian rebels but is bound by an EU arms embargo, which European foreign ministers decided against lifting at a meeting last week.

Mr Kerry arrived in Berlin on Monday night, where he will meet Russia's top diplomat Tuesday, with the Syria crisis topping the agenda.

Russia has also been working on agreeing a trip by Khatib to Moscow, possibly in early March.

Mr Lavrov said the situation in Syria was "at the crossroads" but expressed optimism that a negotiated solution could be found.

The UN human rights chief on Monday criticised the Security Council's failure to take action.

"The Security Council has so far failed with regard to Syria," Ms Navi Pillay told ministers at the start of a regular UN Human Rights Council session in Geneva.

The Syrian observatory for Human Rights said at least 30 Syrian troops and 23 rebels were killed over the past 24 hours in fierce clashes for control of a police academy in the northern Aleppo province.

It also reported that rebels shot down a regime helicopter near a military base elsewhere in the north of the province as insurgents pressed on with attacks on the police academy in the west.

At least 53 combattants - 23 rebels including a battalion commander and 30 Syrian troops - were killed over the past 24 hours in the fighting outside the town of Khan Assal, the Britain-based Observatory said.

The watchdog, which relies on a vast network of activists on the ground and medics, said at least 92 people were killed in violence across Syria on Monday.