"We have proposed a resolution that will impose targeted sanctions on those that are responsible for the crisis with the expectation and hope that they will be incentivized to cooperate," he said.
Khalilzad said he expects the Security Council to vote on the resolution next week. In addition to sanctions and an arms embargo, the resolution would impose travel bans and asset freezes on Mugabe and 11 other senior government and security officials.
South Africa, Russia and China have said they oppose sanctions but have not made it clear whether they would use their veto power to shoot down the resolution.
The Security Council condemned Mugabe's decision to continue with the June 27 run-off election after opposition leader Morgan Tsvangirai withdrew because of violence inflicted on his supporters. Tsvangirai won the first round of voting on March 29 but because he did not win over 50 percent in the disputed results, election laws required a runoff.
On Wednesday, Tsvangirai, the leader of the opposition party Movement for Democratic Change, said he would not consider joining a unity government in which he would become a junior partner to Mugabe. Tsvangirai said Mugabe must stop violence and accept him as the election winner.
Mugabe has held power as leader of his ZANU-PF party since Zimbabwe gained independence from Britain in 1980. Under his power, the economy has faltered and official inflation soars at over 165,000 percent.
The African Union urged two sides to begin power sharing negotiations immediately to resolve the conflict that has gained international attention.
Meanwhile, around 230 victims of violence surrounding the election sought refuge in the U.S. embassy in Zimbabwe's capital Harare.
"We are working with international organizations and local partners to look for safe places to take them," said spokesman Mark Weinberg, according to Reuters. Weinberg said some of them were injured and looking for food and a safe place to stay.
