US says it is not leaning on Syrian opposition, reaffirms support

Syrian opposition parties repeated a call for a stop to bombardments against their forces in the country before any peace-talks could take place.

Talks to end the fighting in Syria would kick-off on Friday, United Nations envoy for Syria Staffan de Mistura said, according to Al-Jazeera.

The negotiations, which had been due to start on Monday, and were expected to last six months, would seek a nationwide ceasefire except against Daesh and al-Nusra front fighters.

Mistura said all parties - except for the two groups designated by the UN as terrorists - would be invited to participate in the ceasefire efforts, with the initial round of discussions expected to last between two to three weeks.

Earlier on Monday, Reuters said the Syrian High Negotiation Committee, the leading opposition coalition, had said it would not attend if it was not allowed to choose its delegates.

Russian officials and the current government in Damascus, under Bashar al-Assad, had called for certain groups - said to be Ahrar al-Sham (with ties to al-Nusra which is an Al-Qaeda affiliate and the Saudi-backed Jaish al-Islam) - which it labels as 'terrorists' to be excluded from the negotiations.

HNC spokesman Salim al-Muslat also asked that air strikes against those groups opposed to Bashar al-Assad and belonging to the opposition stop, as per the UN resolution approved on 18 December.

"We want to realize pure humanitarian matters. They are not preconditions. It is an international resolution at least part of which must be implemented, so we see there is seriousness and good will in this matter," al-Muslat said told Saudi-owned Arabic news channel Arabiya al-Hadath.

The HNC was formed in Saudi Arabia in December.

Some reports alluded to worries that the push for cease-fire talks was cooling.

According to a report by Deutsche Welle, US Secretary of State John Kerry rejected statements from some figures within the opposition that Washington was 'leaning' on them to attend the talks.

"I don't know where this is coming from. Maybe it's a pressure thing or an internal political thing, but that is not the situation," he said.

Kerry reaffirmed the American stance that it was still squarely behind the opposition.

Nonetheless, Kerry warned all parties involved against taking up maximalist positions even before the talks had begun.

"They have to be serious," Kerry said during a visit to Laos, Deutsche Welle reported.

"If they are not serious, war will continue. Up to them - you can lead a horse to water; you can't make it drink."

"I told them you have a veto, and so does he and so you're going to have to decide how to move forward," he said, according to a report from Voice of America.