James McGee met Mugabe at State House, the US embassy in Harare said in a statement.

Ambassador McGee, who replaces the abrasive Christopher Dell, said: “I am thrilled to be in Zimbabwe and am excited about the challenge ahead. Today’s meeting with President Mugabe was the beginning of my work. I am looking forward to working with the people of Zimbabwe during this increasingly difficult period in their lives.

“My job as U.S. Ambassador to Zimbabwe is to work with anyone who wants to cooperate with us to improve the situation here. The U.S. remains committed to seeing free and fair elections next year through which the people of Zimbabwe can express their will’.”

Ambassador McGee, who is black, has previously served in Madagascar, Comoros and Swaziland.

McGee is expected to continue the US’s hard-line stance against President Mugabe’s government which is accused of human rights abuses and suppressing dissenting voices.

The US government has said it is pursuing a policy of “regime change” in Zimbabwe.

The previous US ambassador, Dell, was an outspoken critic of Mugabe’s government. He left for Afghanistan two months ago, telling Zimbabweans: “Keep the faith. Things will change soon.”

The US embassy said McGee would oversee the United States government’s aid programmes in Zimbabwe.

The embassy statement said: “The U.S. will give over $200 million worth of assistance this year. The U.S. will help feed nearly one-in-five Zimbabweans with about $170 million of food aid. HIV/AIDS programs have increased to $31 million this year, including anti-retroviral treatment for 40,000 Zimbabweans.