DOHA (Reuters) – Qatar’s foreign minister on Tuesday welcomed a Russian-brokered agreement for “de-escalation” zones in Syria but said the plan was no substitute for a political transition that would see President Bashar al-Assad step down.

Qatar has been a supporter of rebels who have been fighting to overthrow the Syrian president during six years of civil war.

“It is good to have de-escalation zones but this must be a step to reach a solution to the Syrian crisis and not to use it as an excuse to delay this solution and to postpone the political transition,” the Qatari foreign ministry quoted Sheikh Mohammed bin Abdulrahman al-Thani as telling the Doha-based al-Jazeera network.

The remarks came after talks between the Qatari minister and U.S. Secretary of State Rex Tillerson in Washington.

Russia brokered the deal for de-escalation zones with backing from Iran and opposition supporter Turkey during ceasefire talks in the Kazakh capital Astana last week. The deal took effect at midnight on Friday.

Some fighting has continued in those areas, particularly north of Hama city, but the overall intensity has reduced, the Syrian Observatory for Human Rights monitoring group said.

(Reporting by Tom Finn, writing by Sami Aboudi, Editing by Angus MacSwan)