The United States on Thursday condemned a recent spate of violence in Zimbabwe and blamed President Robert Mugabe's party for the attacks, which are heightening tensions ahead of possible elections this year.

There has been a spate of clashes between Mugabe's ZANU-PF and Prime Minister Morgan Tsvangirai's Movement for Democratic Change (MDC), which has left a dozen people injured in the past two weeks, with a ZANU-PF mob looting shops in Harare this week.

The United States is alarmed by, and condemns, the recent spate of political violence perpetrated by youths and opportunists affiliated with elements of ZANU-PF, the U.S. embassy said in a statement.

MDC members have warned unity government partner and rival Mugabe to drop his ZANU-PF party's plans for an early election, saying the poll could lead to a bloodbath.

Mugabe, 87 later this month, and Tsvangirai were forced into a coalition government two years ago after a disputed poll in 2008 which led to mass violence, a flood of refugees into South Africa and a deeper economic crisis in the resource-rich state.

State media have been reporting that the tenure of the shaky coalition ends on Friday, its two-year anniversary.

Mugabe has proposed a referendum on a new constitution and a general election by June - two years ahead of schedule, although ZANU-PF spokesman Rugare Gumbo told the Financial Gazette: Basically, we are toying around with dates around August.

The MDC first suggested early elections to break deadlocks in the coalition, but says the climate is now not right. It is demanding political reforms before any vote.

While ZANU-PF and MDC trade blame, the U.S. Embassy in Harare said all the parties should renounce violence and urged the police to enforce the law without bias.

We commend the restraint shown by those victimized or affected by these assaults in not responding with violence.

The level of political violence, which had dropped over the last two years, is on the rise again with talk of the election.

Tsvangirai says ZANU-PF militants, led by war veterans, are targeting MDC structures and accuses the police of taking sides with ZANU-PF.

A police spokesman said this week the MDC was responsible for the