JUBA, Aug. 4 (Xinhua) -- South Sudan's parties to the unity government on Thursday extended the transitional period by two years.

President Salva Kiir said his regime is not extending the transitional period to stay in office but to prepare the country for an election and peaceful transition of power.

"We have decided to prepare the soil over the next 24 months to plant the seeds for the South Sudan election with a unified army, visionary constitutions, and firm understanding of our country upon which to build a government that can complete the war on poverty, ignorance, and hopelessness," Kiir said in Juba, the capital of South Sudan.

The South Sudanese leader was speaking after signing a roadmap to the conduct of election and extension of the transitional period of the government for 24 months.

Kiir signed on behalf of the ruling party - Sudan People's Liberation Movement/Army- In Government (SPLM-IG), First Vice-President Riek Machar signed on behalf of Sudan People's Liberation Movement/Army-In Opposition (SPLM-IO), while Gabriel Changson Chang signed for the opposition coalition - South Sudan Opposition Alliance (SSOA)

The president called on holdout groups who are not signatories to the peace pact to join the peace process to bring a peaceful transition to the country.

Machar said the extension of the transitional period is for the agreement to be genuinely implemented as the implementation of the agreement is lagging.

He called on President Kiir to provide free political space for the citizens to bring a level ground for the parties to compete in elections.

"I have not been invited to go for a rally and the reason is people are afraid to hold political rallies, you cannot transform, political parties cannot survive if there is no political space," Machar said.

South Sudan descended into violence in December 2013 following a political dispute between Kiir and his then deputy Machar, leading soldiers loyal to the respective leaders to fight.

The conflict has killed tens of thousands and displaced more than 2 million people both internally and externally.