The United States, Russia and seven other would-be Syria mediators ended a 4½-hour meeting on Saturday without agreement or concrete steps to match what America’s top diplomat described as the “urgent crisis” in the city of Aleppo. Instead, the envoys said only that new ideas had been proposed and more discussions planned.

The lacklustre result from the gathering in Switzerland highlighted the world’s inability to find a peaceful path out of a conflict that has killed as many as half a million people, contributed to Europe’s worst refugee crisis since the second world war, and created a vast space of instability that the Islamic State group has exploited.

With the Syrian and Russian governments pressing an offensive against rebel-held parts of Aleppo, no one predicted a breakthrough. Yet after last month’s collapse of a ceasefire and even US charges of Russian war crimes, the US secretary of state John Kerry’s portrayal of the result as “exactly what we wanted” sounded unconvincing.

“Nobody wants to do this in a sloppy way,” Kerry said of his new diplomatic effort, no longer between just Washington and Moscow but designed to include all the major international players in Syria’s civil war. Saturday’s talks included top envoys from Saudi Arabia, Iran, Turkey, Qatar, Iraq, Egypt and Jordan.

Kerry said the discussion was driven by the “urgency of Aleppo, the urgency of trying to find something that works other than military action”. Ministers offered suggestions that “really might be able to shape some different approaches” he said, without going into detail.

No official news conference or joint statement followed the meeting. Kerry said contacts, but not necessarily a meeting, would start anew next week.

Days of deadly airstrikes in Aleppo prompted Kerry last month to end bilateral US-Russian engagement on Syria, including discussions over a proposed military alliance against Isis and al-Qaida-linked militants in Syria. Last week he accused Russia of war crimes for targeting hospitals and civilian infrastructure in Syria.

Nevertheless, Kerry reunited with the Russian foreign minister, Sergey Lavrov, at the lakeside Beau-Rivage Palace in Lausanne, speaking with the Russian for almost 40 minutes before the larger gathering. For all the talk in Washington about a possible plan B, US hopes for diplomatic progress appeared to rest squarely on Russia’s cooperation.

“There are a few ideas we discussed today in this circle of countries that can influence the situation,” Lavrov told Russian news agencies. “We agreed to continue contacts in the next few days aiming at agreements that could advance the settlement. We spoke clearly in favour of a quick launch of a political process.”

Residents of opposition-held eastern Aleppo have faced daily violence as the Syrian president Bashar al-Assad’s government seeks to take full control of the country’s largest city.

On Saturday, Syrian and Russian airstrikes hit several rebel-held neighbourhoods during clashes on the frontlines in Syria’s largest city and former commercial centre, according to the Britain-based Syrian Observatory for Human Rights and the Aleppo Media Centre, an activist collective.

