WASHINGTON: US president-elect Barack Obama Wednesday telephoned UN Secretary-General Ban Ki-moon plus the presidents of Colombia, Nigeria, Senegal and South Africa, his office said.

Obama returned their calls "and expressed his appreciation for their congratulations on his election," the Democrat''s transition office said in a statement, offering no further details.

Obama has been pursuing a near-daily round of calls to foreign leaders since his election triumph over Republican John McCain on November 4.

Apart from Ban, the latest calls were to Colombian President Alvaro Uribe, Nigerian President Umaru Yar''Adua, Senegalese President Abdoulaye Wade and South African President Kgalema Motlanthe.

A source close to Uribe told AFP that the pair spoke for about 10 minutes on NAFTA (North American Free Trade Agreement), the trade pact Obama has indicated he is willing to re-negotiate when he takes office in January.

Uribe had been open in his support for McCain and now faces increased scrutiny over human rights abuses in his nation from Obama, who opposes a US-Colombia free trade pact currently frozen in the Democratic-led Congress.