ROME -- As new reports of violence flowed from Syria, Secretary of State John Kerry telephoned leaders in Europe and the Middle East on Wednesday to lay the ground for a conference between rebels and the Syrian government, sponsored by the United States and Russia, that he hoped would begin within a month.
Mr. Kerry and his Russian counterpart, Foreign Minister Sergey V. Lavrov, announced a new diplomatic effort to end the two-year-old Syrian conflict after intense discussions on Tuesday in Moscow. Mr. Kerry then flew to Rome, where aides said he would announce on Thursday a 25 percent increase in American humanitarian aid to Syrian civilians whose lives have been upended by the crisis. The additional aid, according to a State Department statement, would bring the American total to about $510 million.
The American ambassador to Syria, Robert S. Ford, who accompanied Mr. Kerry during his talks in Moscow, flew to Istanbul to press representatives of the Syrian opposition to agree to talks with an envoy of President Bashar al-Assad of Syria. There were initial indications, at least, that both sides were not opposed to the idea.
Syria's official news agency, SANA, reported it with the headline: "Lavrov, Kerry: Negotiations Are Vital Tool to Rreach Settlement."
The main political opposition group, the National Coalition of Syrian Revolutionary and Opposition Forces, said in a statement that it welcomed "all international efforts calling for a political solution, which will achieve the aspirations of the Syrian people for a democratic state that begins with the removal of the Assad regime." But the statement also said: "It is important to note that the Assad regime rejected all initiatives that have been presented thus far to resolve the crisis."
The special Syria peace envoy from the Arab League and the United Nations, Lakhdar Brahimi, who has been expected to resign in frustration over his failed efforts to make any headway, issued a statement welcoming the American-Russian proposal on Syria, calling it "the first hopeful news concerning that unhappy country in a very long time."
It remains uncertain whether the two sides in an increasingly brutal civil war will even agree to substantive talks, but Russia's support for a transitional government -- which Mr. Lavrov suggested would not include Mr. Assad -- raised hopes of American officials.
Mr. Lavrov, whose government has been Mr. Assad's primary foreign backer, spoke with the Syria foreign minister, Walid al-Moallem, before the agreement was announced in Moscow after extended meetings that Mr. Kerry had held with President Vladimir V. Putin and Mr. Lavrov.
"I think we, hopefully, found a cooperative way forward to maybe try – I can't guarantee you can – but try to bring people together to deal effectively with Syria and hopefully end bloodshed and see if there isn't a way to find a way forward," Mr. Kerry told workers from the American Embassy in Moscow on Wednesday before flying to Rome. "It is not easy. Nothing is easy in this process."
The Obama administration has not reversed its demand that Mr. Assad resign, but the proposal Mr. Kerry negotiated with the Russians in effect accepts the premise that Mr. Assad's government would at least have a say in the negotiations, if they begin, just as Russia accepted that Mr. Assad would most likely not be in power if an agreement is reached on forming a transitional government.
Mr. Kerry spoke on Wednesday with Prime Minister David Cameron of Britain and the foreign minister of Qatar, among others. On Thursday, he will meet in Rome with Foreign Minister Nasser Judeh of Jordan, where aides to Mr. Kerry said he would officially announce the increased aid package, which includes a substantial chunk for the Syrian refugees in Jordan.
The intensified diplomacy was taking place against a backdrop of new fighting in Syria, with unconfirmed reports that the top leader of the Nusra Front, a jihadist insurgent group that officially aligned itself with Al Qaeda last month, and which has been blacklisted by the United States, had been wounded in a bombing by Syrian forces in the southern Damascus suburbs.
The Syrian Observatory for Human Rights, a Britain-based group with a network of contacts inside Syria, said the Nusra leader, Abu Mohammed al-Jawlani, was one of several fighters believed to have been wounded in the bombing. Efforts to corroborate the Observatory's account were not immediately successful.
Anti-Assad activist groups also reported that militants from Hezbollah, the Lebanese Shiite group that is an ally of Mr. Assad, had committed a massacre outside the Syrian town of Qusayr near the Lebanese border. That area has been riven for weeks by sectarian clashes between rebels from Syria's Sunni majority and forces loyal to Mr. Assad, whose minority Alawite sect is an offshoot of Shiite Islam.
The Local Coordinating Committees, which supports the uprising against Mr. Assad, said Hezbollah fighters in the Qusayr area "claimed the lives of 30 martyrs, most of them children and women, after Hezbollah forces killed them while they were fleeing the city and kidnapped their bodies."
There was no comment from Hezbollah, but its leaders have warned that they would fight on Mr. Assad's behalf and retaliate for what they have called the desecration of Shiite religious sites in Syria by insurgents.
Elsewhere in Syria on Wednesday, negotiations were under way aimed at freeing four United Nations peacekeepers abducted on Tuesday by Syrian insurgents in the disputed Golan Heights region between Israel and Syria. Josephine Guerrero, a spokeswoman for the United Nations departments that oversee its peacekeeping operations, said the United Nations "has had indications that they remain unharmed."
The Syrian government reported that it was in the process of resolving a shutdown of Internet and phone service in the country that had started late Tuesday. SANA attributed the problem to a "malfunction in an optic cable."
Foreign monitors of global Internet traffic said on Tuesday that the shutdown appeared to have been an intentional action by the Syrian government. Such shutdowns have happened before when the military was undertaking major actions against insurgents.
Steven Lee Myers reported from Rome, and Rick Gladstone from New York. Anne Barnard, Hania Mourtada and Hwaida Saad contributed reporting from Beirut, Lebanon.
This article originally appeared in The New York Times.