Mediators are hoping to revive crisis talks between Zimbabwe's ruling party and the opposition.
Nigerian Foreign Minister Sule Lamido met President Mr Robert Mugabe, describing the meeting as "enlightening" and is optimistic the talks could be restarted.
Zimbabwe is suffering its worst economic crisis since 1980, a situation worsened by opposition claims that Mr Mugabe fixed the March presidential election.
Nigerian President Mr Olusegun Obasanjo and South African President Mr Thabo Mbeki sent mediators to Harare in April for talks, but hopes for progress faltered over the election issue.
The opposition Movement for Democratic Change (MDC) is refusing to accept Mr Mugabe's victory and is filing a court challenge alleging voting was swayed by violence, intimidation and rigging.
The MDC is demanding a new election held under international supervision within a year. Official results showed opposition leader Mr Morgan Tsvangirai losing by some 400,000 votes. Mr Mugabe has refuses to consider new elections.
Severe food shortages have been caused by farm disruptions and erratic rains. The World Food Programme estimates half of Zimbabwe's 12.5 million people will need food aid to avert starvation this year.
AP
