The United Nations envoy to Syria said it is unclear when the next round of Syrian peace negotiations will take place, and time may be running out on the talks.
The last round of talks between the Syrian government and opposition broke up in April as government forces, backed by Russia, escalated their assault on rebel-held Aleppo.
"I'm still aiming within July, but not at any cost and not without some guarantees," Staffan de Mistura told reporters after briefing the 15-nation UN Security Council on the peace efforts on June 29.
"When you convene a conference...you want to make sure that it has good chances of success," he said.
Mistura suggested that time may be running out on finding a solution, with two of the strongest proponents -- U.S. President Barack Obama and UN Secretary-General Ban Ki-moon -- wrapping up their terms in office.
A "cessation of hostilities" brokered in February brought peace to much of Syria for two months but has largely broken down with the resumption of war in many areas.
Negotiations have stumbled over the role for President Bashar al-Assad, who is supported by Russia and Iran but who Western governments want to step down.