Addresssing the Syria conflict at the Munich Security Conference on Sunday, the UN special envoy for Syria, Staffan de Mistura, said one thing he was missing at the moment was a "clear US strategy."

"Where is the US in all this?" de Mistura asked. "I can't tell you because I don't know."

One month into US President Donald Trump's four-year term in office, the new administration is still trying to work out its priorities on the conflict, de Mistura said.

The top three US priorities include fighting self-styled "Islamic State" (IS) jihadis, "how to limit the influence of some major regional players and how to not to damage one of their major allies in the region," de Mistura said, shedding no light on exactly who the regional player or major ally were.

The first reference, however, appeared to be to Iran, with the second likely to be either Turkey or Saudi Arabia.

Inclusive political solution

Looking ahead to the new round of UN-led peace talks to start in Geneva on Thursday, de Mistura stressed that, ultimately, an inclusive political solution would be key in ending the six-year conflict.

"Even a ceasefire with two guarantors can't hold too long if there is no political horizon," he said, referring to the fragile accord agreed between Russia and Turkey in December.

Any political solution has to be inclusive to be credible, de Mistura said, stressing that and the ceasefire deal as well as last week's peace talks in Astana - organized by Russia, Turkey and Iran - provided an opportunity that should be investigated further.

Assad question remains

Meanwhile, the US envoy for the anti-IS coalition, Brett McGurk, acknowledged that Trump's administration is "re-looking at everything, which is a very healthy process from top to bottom."

"We will be very selfish about protecting and advancing our interests," he told the same forum in southern Germany.

Under former US President Barack Obama, Washington insisted that Syrian President Bashar al-Assad be removed from office - a stance that put the White House at odds with Moscow, which backs the Syrian leader.

Trump, however, has called for closer cooperation with Russia to combat IS in Syria and Iraq, leaving the Assad question unanswered.

Rocket-fire in Damascus

De Mistura's comments on Sunday came as the Syrian army traded rocket-fire with rebels in and around the capital, Damascus. As many as 16 people have been killed in the latest attack, which began on Saturday.

The Syrian Observatory for Human Rights (SOHR), as well as a medical worker, called it the biggest attack on the capital's northeast suburb of Qaboun in more than two years. It also marked the highest death toll in the area since 2014.

The leading Syrian opposition body, the High Negotiations Committee (HNC), lambasted the escalating attacks as a "bloody message," aimed at sabotaging next week's peace talks.

More than 310,000 people have died since a popular uprising in 2011 against Assad turned into all out war. More than half the Syrian population has been forced to flee their homes, sparking the ongoing refugee crisis in Europe.

ksb/sms (AP, AFP, dpa)