Syrian government and opposition parties at peace talks in Geneva are expected to agree on Thursday to a document drawn up by a U.N. special envoy outlining basic principles in what one diplomat described as a "baby step" forward.

With a fragile ceasefire in place in Syria, negotiations are due to adjourn on Thursday after almost two weeks of discussions and to resume in April.

The talks are part of a diplomatic push launched with U.S. and Russian support to end more than five years of war in Syria that has killed more than 250,000 people, created the world's worst refugee crisis and bred the rise of Islamic State.

Progress has been slow, with government officials avoiding any talk on the divisive issue of a political transition or the fate of President Bashar al-Assad, who opposition leaders say must leave office.

But U.N. envoy Staffan de Mistura has said he aimed to establish if there were any points held in common by the different parties and if successful, to announce them.

"Basic principles have been laid out. De Mistura wants to announce that all sides have agreed so that he can move on to the transition issue at the next round," said a senior Western diplomat. "It's a baby step, but a necessary step. It's not a bad result."

The diplomat, speaking on condition of anonymity, said the document contains 10-12 points ranging from agreeing to a united national army, the need to fight terrorism, and ensuring a democratic non-sectarian state with equal rights for all.

A Middle Eastern and another Western diplomat also said they expected de Mistura to announce broad principles enabling him to move on to the subject of a political settlement.

Randa Kassis, who heads a Moscow-backed opposition group, confirmed de Mistura had informed delegates of the basic principles paper. Government negotiator Bashar Ja'afari said on Wednesday that a U.N. document would be reviewed in Damascus ahead of the next round of talks.

After meeting European Union foreign policy chief Federica Mogherini, a rare encounter with a senior Western figure, Ja'afari sounded positive saying he believed the round of talks had broken the diplomatic impasse.

But he was told by Mogherini and de Mistura that accelerating a political transition in Syria was the only way to defeat insurgent groups like Islamic State.