Mr Zenawi said Ethiopia had been testing the jamming equipment
Ethiopia has admitted it is jamming the Voice of America's (VOA) broadcasts in Amharic, accusing the radio station of engaging in "destabilising propaganda".
Prime Minister Meles Zenawi said Ethiopia had been testing jamming equipment, but there had been no formal decision to block the US station.
The Amharic Service has experienced interference since late February.
Mr Meles also compared the VOA's transmissions to broadcasts in Rwanda in the mid-1990s that incited genocide.
"We have for some time now been trying to beef up our capacity to deal with this, including... jamming," Mr Meles said on Thursday.
In a statement, VOA director Danforth Austin said that any comparison of VOA programming to Rwandan broadcasts inciting genocide in the 1990s was "incorrect and unfortunate".
"The VOA deplores jamming as a form of media censorship wherever it may occur," he said, adding that the station's Amharic Service was required by law to provide accurate and objective information.
The VOA and other foreign media organisations say broadcasts in Amharic - the country's most widely spoken language - have been jammed around elections in the past.
The next polls in Ethiopia are in May and human rights groups say there has been a crackdown on the press.
The last elections saw opposition accusations of widespread rigging.
Thousands of opposition supporters were arrested after protests and some western countries reduced aid to Ethiopia.
Mr Meles also rejected calls to free opposition leader Birtukan Medeksa from jail.
She was sentenced to life in prison in 2005 after the election protests, pardoned in 2007 and then re-imprisoned in 2008.
The prime minister said she would remain in prison "permanently" and that diplomats and journalists could not visit her - the same rules as for other prisoners in Ethiopia.
Separately, Mr Meles again denied claims in a recent BBC report that he had ordered the diversion of food aid money to buy arms to fight the government in the 1980s.
"We did not need to [do it]. We were not short of ammunition or arms. That was never our problem. Our main problem was that we were operating in an environmentally very fragile area unable to feed itself," he said.