The plan outlines President Abd-Rabbuh Mansour Hadi handing over powers to a vice president and Houthis withdrawing from cities which they captured in 2014.
Thousands of people took to the streets of the southern cities of Taiz and Aden in Yemen in support for President Abd-Rabbuh Mansour Hadi. The protesters rejected a UN envoy's peace proposal to mend ties between the government and Houthi rebels, saying the plan would only "legitimise the rebels' 2014 coup".
Saudi-backed Hadi has been battling Houthi rebels who ousted him and took control of the capital Sanaa and other provinces in 2014. The Houthis, followers of a particular Shia sect of Islam, claimed the government was corrupt and pandering to a Saudi agenda.
Hadi went into self-imposed exile in Saudi Arabia and other Arab states for six months in 2015 after the rebels attacked Aden. He and his government are temporarily based in Aden, which is Yemen's largest port city.
"Today we went out to support the legitimate leadership represented in brother [President] Abd-Rabbuh Mansour Hadi," one of the protesters, Ibrahim al-Gabry, said in Taiz. Many protestors held placards denouncing the UN envoy's peace plan. "The UN peace plan paves the way for war," read one.
UN Special Envoy for Yemen Ismail Ould Cheikh Ahmed has chalked up a plan which proposes that Hadi hand over powers to a deputy and in return the Houthis withdraw from the main cities in their control since 2014.
According to Al Jazeera, the UN's proposal includes appointing a new vice president who would take over from Hadi. The new deputy would then appoint a prime minister to head a representative government.
The demonstration in the southern city of Aden and other locations coincided with Cheikh Ahmed's visit to Sanaa earlier on Thursday to discuss efforts for peace between Houthis and Hadi's party.
On Saturday, Hadi denounced the proposed roadmap as he said it would reward Houthis for staging a rebellion. He said the new peace plan is a departure from the earlier UN Security Council's resolution 2216 which calls for the Houthis to withdraw from areas they seized in 2014.
Clashes between Houthis and pro-Hadi forces are still ongoing in Taiz, the second largest city in Yemen. Houthis control the entrances to the city and a number of other areas.
The Houthis have called the plan a "basis for discussion" despite containing "fundamental flaws".
While both parties unofficially rejected the proposal last week, a senior diplomat at the UN told Reuters that Saudi Arabia appeared broadly to accept the initiative and had encouraged Hadi to deal with it.