BEIRUT (Reuters) - Syrian rebel factions on Friday condemned a declaration of federalism in Kurdish-controlled regions of northern Syria and vowed to resist it by force, a day after those areas voted to seek autonomy.

A statement from a number of Syrian insurgent groups, some of whom are represented in the main opposition body that is participating in peace talks, said the federalism announcement was a “project to divide” Syria.

Syria’s Kurdish-controlled northern regions voted on Thursday to seek autonomy under a federal system, drawing rebukes from the main opposition’s High Negotiations Committee, the Damascus government, Turkey and Washington.

The rebel statement said this was “exploitation” of the Syrian uprising that began five years ago and descended into civil war, and condemned what it said were attempts by “groups... which took control of parts of Syrian land to establish their racial, nationalist and sectarian entities”.

It compared Kurdish groups to Islamic State, and said the YPG militia and its political arm the PYD were terrorists.

The YPG, which has been backed by Washington in its fight against IS, has beaten back the jihadists to control swathes of northern Syria, but the PYD has so far been excluded from peace talks that began this week in Geneva.

The vote to unite three Kurdish-controlled provinces in a federal system appears aimed at creating a self-run entity within Syria, a status that Kurds have enjoyed in neighboring Iraq since the fall of Saddam Hussein in 2003.

The three Kurdish-controlled regions agreed at a conference in Rmeilan in northeast Syria to establish the self-administered “federal democratic system of Rojava - Northern Syria”, officials announced. Rojava is the Kurdish name for north Syria.