German Chancellor Angela Merkel is continuing her five-day tour of sub-saharan Africa today with a visit to Johannesburg. There she's due to hold talks with South African President Thabo Mbeki, and is expected to press him to take a tougher line in dealing with neighboring Zimbabwe. Earlier, on a stop in Ethiopia, the Chancellor urged African leaders to show greater prudence in spending European Union funds, which account for half of all development aid to the continent.