Harare, Zimbabwe (CNN) -- Explosives tossed Sunday at the residence of Finance Minister Tendai Biti failed to detonate, according to officials of Prime Minister Morgan Tsvangirai's Movement for Democratic Change.
The explosives hit the outer wall of Biti's residence, MDC spokesman Nelson Chamisa said.
Biti, who serves in the post as part of the coalition government formed by Tsvangirai and President Robert Mugabe, was in South Africa at the time, said MDC Director General Toendepi Shonhe.
"It's a clear intimidatory tactic" reminiscent of the approach of Mugabe's Zanu PF party to political opponents, Shonhe said.
Police spokesman Wayne Bvudzijena said he was trying to verify what happened. Chamisa said no arrests had been made so far in connection with the incident.
Biti, who was appointed finance minister by Tsvangirai in the coalition government formed by the MDC and Zanu PF, has clashed with Mugabe over salaries for government workers and the president's call for an election this year.
Biti defied Mugabe's proposal to double the salaries of civil servants. He also rejected the election call, saying the government could not afford it.
Last week, Mugabe told traditional leaders that Biti was trying to usurp presidential powers.
In July 2009, Biti received an envelope containing a written note and a 9mm bullet. The note advised Biti to "prepare your will." No one was ever arrested in that case.