The United States will consider more sanctions against Zimbabwe if President Robert Mugabe does not follow through on commitments to set up a power-sharing government, the US State Department said Monday.

"Should Mugabe renege on this power-sharing agreement, the United States ... is prepared to impose additional sanctions," State Department deputy spokesman Robert Wood said.

Mugabe's Zanu-PF party and the opposition leader and head of the Movement for Democratic Change (MDC), Morgan Tsvangirai, have traded blame for the lack of progress in establishing power-sharing government.

Tsvangirai did not attend a meeting in Swaziland on Monday, saying the Mugabe government would not issue him a passport. The Zanu-PF said Tsvangirai has been provided with emergency travel documents.

Former South African president Thabo Mbeki is leading the effort to broker an agreement between the two sides and break the impasse over how many and which cabinet posts MDC officials will serve in.

"We're very committed to seeing this process go forward in a positive way that will reflect the will of the Zimbabwean people," Wood said.