Attacks in Syria's third city of Homs, which left dozens dead on February 25, aimed to "spoil" peace talks under way in Geneva, the UN's envoy said.
The suicide assaults on the headquarters of state security and military intelligence in the city killed dozens of people, including a top Syrian intelligence chief, overshadowing the Geneva talks, Radio Free Europe reports.
Asked if the attacks would affect the UN-sponsored talks, Staffan de Mistura said: "I hope not, but it was tragic."
He added, "Every time we are having talks or negotiations there is always someone who tries to spoil. We were expecting that."
Syrian government negotiator Bashar al-Jaafari also said the attacks were a message aimed at the peace talks. "This crime won't pass unnoticed," he told reporters before meeting de Mistura in Geneva.
Syria's former Al-Qaeda affiliate Fateh al-Sham Front, known before as the Al-Nusra Front, claimed the attacks which targeted and killed General Hassan Daabul, a close associate of President Bashar al-Assad.
Britain-based Syrian Observatory for Human Rights said 42 people were killed, but provincial Governor Talal Barazi put the toll at 32 people dead and 24 wounded.
De Mistura was preparing more separate meetings with Syrian government and opposition negotiators.
At the last such UN-sponsored talks the two sides did not meet for face-to-face negotiations, with de Mistura shuttling between them as a mediator.
