Zimbabwe's new prime minister, Zimbabwe Morgan Tsvangirai, says he is working to reassure President Robert Mugabe that he has nothing to fear from the power-sharing agreement they have signed.
Mr Tsvangirai says Mr Mugabe is obssessed with the idea there is an attempt to overthrow him.
He says the people of Zimbabwe want the new arrangement to work because people are suffering.
Meanwhile, the European Union will not immediately end its sanctions against Zimbabwe despite the power-sharing deal signed in the capital Harare on Monday.
EU foreign ministers said sanctions would continue until the new Zimbabwean government took steps to restore democracy and the rule of law.
United States Assistant Secretary of State for African Affairs Jendayi Frazer issued a similar statement, saying Washington wanted to work with Zimbabwe but a number of conditions had to be met first.
On Monday evening, Zimbabwe's rival political parties signed a landmark power-sharing deal that will result in President Robert Mugabe ceding some of his powers for the first time in nearly three decades of iron rule.
Mr Mugabe, main opposition Movement for Democratic Change leader Morgan Tsvangirai and Arthur Mutambara, who heads a breakaway MDC faction, signed the agreement at a Harare hotel after weeks of tense negotiations.
The audience in the hotel cheered as the agreement was signed in front of African leaders, including Tanzania's Jakaya Kikwete, chairman of the African Union, and South African President Thabo Mbeki, who brokered the deal.
Mr Mugabe and Tsvangirai last week agreed on the deal to end a deep political crisis compounded by the veteran leader's disputed and unopposed re-election in June.
Mr Tsvangirai, speaking after the signing of the agreement, says his first priority will be to tackle devastating food shortages and open the country to foreign aid.