Yemen’s UAE-backed separatists on Friday announced the start of a two-year transitional period towards declaring an independent state after their forces seized large areas of the country’s south.

The Southern Transitional Council (STC), whose forces came under fire from deadly Saudi-led coalition airstrikes on Friday, said the process would include dialogue and a referendum on independence.

“We announce the commencement of a transitional phase lasting two years, and the Council calls on the international community to sponsor dialogue between the concerned parties in the South and the North,” STC president Aidaros Alzubidi said in a televised address.

However, he warned the group would declare independence “immediately” if there was no dialogue or if southern Yemen again came under attack.

“This constitutional declaration shall be considered immediately and directly effective before that date if the call is not heeded or if the people of the South, their land, or their forces are subjected to any military attacks,” Alzubidi said.

SCT forces seized large swathes of Yemen’s south, run by a fractious government with competing agendas, in a lightning and largely unopposed offensive last month.

Iran-backed Houthi rebels forced the government out of the country’s north in 2014, prompting a vain military intervention by the Saudi-led coalition.