Tsvangirai plans to make his case Friday in a meeting with U.S. President Barack Obama as part of a three week tour of Western countries. He also will meet Thursday with Secretary of State Hillary Rodham Clinton.
In a speech at the Council on Foreign Relations, Tsvangirai said his country was implementing Democratic reform. He said two ministers close to Mugabe should resign but did not say the president should quit. He warned that the government could collapse without outside support.
Western leaders have long isolated Zimbabwe, accusing Mugabe of trampling on democracy.
A campaign for the United States government to lift targeted sanctions imposed on President Robert Mugabe and his officials has suffered a major setback after the US Senate resolved to maintain the restrictions.
In a resolution this week, the US Senate on Tuesday said travel bans, financial restrictions and an arms embargo against Zimbabwe, Mugabe and his officials would remain in place until there was provable progress towards the restoration of the rule of law and respect for human rights.
The US Senate said suspension of non-humanitarian government-to-government assistance would remain in place.
The US is insisting on demonstrable progress towards restoring the rule of law, civilian control over security forces as well as respect for human rights in Zimbabwe.
The Senate supported the continuation and updating of financial sanctions and travel bans targeted against individuals responsible for the deliberate breakdown of the rule of law, politically motivated violence, and other ongoing illegal activities in Zimbabwe.
The resolutions were co-sponsored by Senator Peter Feingold, Senators Johnny Isakson, John Kerry, James Inhofe, Sheldon Whitehouse, Bill Nelson, Roland W. Burris, Richard J. Durbin, Benjamin L. Cardin, Mel Martinez and Sam Brownback.
However, the US Senate noted that there had been some progress towards the implementation of the Global Political Agreement (GPA), including positive steps taken by the Ministry of Finance in crafting the new economic blueprint dubbed Short Term Economic Recovery Program (STERP).
The Senate also noted as positive the replacement of the Zimbabwe dollar with multiple foreign currencies such as the US dollar, the British Pound Sterling, the South African Rand and the Botswana Pula.
The senators said the full implementation of the GPA continued to be obstructed by hardliners in the government and important issues regarding the appointments of Reserve Bank of Zimbabwe (RBZ) Governor and the Attorney General (AG) remained unresolved.
The Senate said it remained worried by the arrests of journalists and human rights activists and the delay in swearing into office of properly designated officials nominated by the Movement for Democratic Change (MDC).
It also accused security forces of continuing to operate outside the rule of law.
The Senate said the media environment and access to the media remain restricted while land invasions were still continuing in some provinces in the country.
However, the US Senate said its government would continue to provide humanitarian aid and resources to non-governmental entities and would provide concrete financial and technical assistance in response to requests from the people of Zimbabwe and civil society in their efforts to draft and enact a new constitution.
Prime Minister Morgan Tsvangirai has visited Washington and other western governments on a mission to convince the governments to lift sanctions against Zimbabwe.