In an interview with Reuters, the veteran leader also said he would "never" replace two key officials that the opposition Movement for Democratic Change (MDC) says he agreed to change under a power-sharing deal in the Southern African country.
The Bush administration, which left power in January, slapped sanctions in 2003 on Mugabe and other prominent Zimbabweans accused of undermining democracy and later extended them. The European Union imposed measures of its own.
The power-sharing pact installed MDC leader Morgan Tsvangirai as prime minister in February, but the sanctions remain. An EU delegation that visited Zimbabwe this month said it was waiting to see that human rights abuses had ended.
Mugabe, visiting New York for the annual United Nations General Assembly, said he would tell the world body that the sanctions were unjustified and should be lifted.
But he added: "We are giving time to the administration of [Barack] Obama to make their decision. They inherited sanctions, they found them on his desk and we don’t expect him to get rid of them that quickly."
Obama administration officials have given no indication they are considering lifting sanctions.
Mugabe, in power since independence from Britain in 1980, has blamed sanctions for the economic woes of Zimbabwe, which needs billions of dollars for recovery. Western countries accuse Mugabe of wrecking the African nation through mismanagement.
The Zimbabwean leader strongly defended his decision to retain two allies, central bank governor Gideon Gono and attorney general Johannes Tomana, despite what the MDC says is an agreement that they would go.
"I appointed [Gono] long before the [power-sharing] agreement had come into being … and the same with the attorney-general. And there’s nothing wrong that they have done," Mugabe said.
"I don’t see any reason why they should be discharged and new people found to replace them. And so I have laid down my foot and said no, they will never be. You see, I won’t let them go."
The MDC has accused Gono of fueling hyperinflation by printing money and Tomana of presiding over the prosecution of rights and opposition activists.
Mugabe also defended his refusal to swear in Roy Bennett, MDC treasurer-general, as deputy agriculture minister, saying he faced criminal charges. If Bennett, who is due to stand trial next month on terrorism charges, was acquitted, there would be "no objection" to his appointment, he said.
Despite the disputes with the MDC, Mugabe said he had a working relationship with Tsvangirai.
"We are very good partners in the inclusive government and we understand each other," he said. "Not that we agree every time, but there is more room for agreement just now than disagreement and we trust each other … He tells me the truth, I tell him the truth."
Mugabe (85) declined to say whether he would run again in the next general election, expected in 2011.
"That’s what I won’t say — if I am going to run or I’m not going to run," he said. "It would be bad tactics to say so, political tactics. I don’t want also to divide my [Zanu-PF] party at the moment." – Reuters