(Adds SPLM reaction paragraph 8) By Andrew Heavens KHARTOUM, Oct 21 (Reuters) - Sudan's vice president accused former southern rebels on Sunday of building up their forces and escalating tension, 10 days after they withdrew their ministers from the country's government sparking a political crisis. Vice President Ali Osman Mohamed Taha urged the Sudan People's Liberation Movement (SPLM) to return to Khartoum and restart work on implementing a fragile north-south peace deal. The SPLM withdrew its ministers from the coalition Government of National Unity on Oct. 11, saying its main partner was stalling on rolling out the Comprehensive Peace Agreement, a deal signed in 2005 that ended Africa's longest civil war. Taha hit back in a two-hour news conference, saying that the peace deal was on track and that it was the SPLM who were now delaying it by walking out of the coalition government. "The SPLM says it will not go back to war," said Taha, speaking through an interpreter. "But the reality on the ground indicates that the SPLM is redeploying its forces and building them up between the Blue Nile and the While Nile in Bahr el-Ghazel," a region near the north-south border. "We are calling on the SPLM to practise self-control and to stop the escalation of the situation." Taha urged the SPLM to review its decision to withdraw from government, saying it was in the interest of neither the Sudanese people nor the citizens of southern Sudan. SPLM Deputy Secretary-General Yasir Arman described Taha's allegations as "totally baseless", and said SPLM Chairman Salva Kiir would respond to them in detail "very soon". ESCALATING WAR OF WORDS Taha's statement, the first by the government since the breakup of crisis talks between the president and the SPLM on Thursday, marked a significant escalation in the war of words between the two sides. Taha also hit out at the SPLM's record in the south, accusing it of neglecting citizens and funnelling funding towards party members. Deteriorating relations in recent months between the SPLM and its partner in power, the dominant National Congress Party, have sparked fears for the future of the peace deal. Commentators have warned a collapse of the pact would have a devastating impact on security across Sudan, including its war-torn western Darfur region. The two-decade civil war that the CPA ended killed 2 million people and drove 4 million from their homes. The SPLM last week accused the National Congress Party of stalling on a list of protocols to the peace deal including the location of their shared border, the management of oil fields, funding for a census and the fate of political prisoners. During Taha's news conference, officials handed out copies of an "Implementation of the CPA Progress report", which Taha said showed the government was on track in delivering on its commitments. Talks between Kiir and President Omar Hassan al-Bashir to try to resolve the crisis broke up on Thursday without resolution. SPLM officials told Reuters they hoped to reconvene the talks next week.