European Commission President Jose Manuel Barroso was quoted by Reuters as telling the United States on Friday it could not solve world problems alone, urging it to honour foreign aid pledges and prove it was committed to the United Nations. The head of the European Union's executive body said there were signs the transatlantic rift over the U.S.-led Iraq war was healing but called on both sides to work harder to mend ties. "America will not be more successful in achieving its objectives by taking the unilateral path. Europeans need to spend a bit more time matching their words to deeds," he told the New York-based think-tank Council on Foreign Relations, according to Reuters. As Portugal's ex-prime minister, the centre-right Barroso supported the United States over the Iraq war, which President George W. Bush launched in 2003 without U.N. backing and in the face of opposition from France and others. But Barroso denied the episode had shown the shortcomings of the United Nations, and urged Washington to lead efforts by U.N. Secretary General Kofi Annan to revamp the world body to help it better tackle poverty, conflict and human rights abuses. --More 2147 Local Time 1847 GMT