Ethiopia’s Prime Minister Meles Zenawi has accused the official opposition of collaborating with armed insurgents.
His comments came after an opposition leader complained in parliament about harassment in the Oromia region.
Mr Meles also mocked foreign press coverage of events in the south-east Ogaden region where rebels claim to have battled the army over the weekend.
Some groups have taken up arms in the Oromia and Somali-speaking Ogaden regions in pursuit of greater autonomy.
In the parliamentary session, broadcast live on Ethiopian television, the prime minister said the opposition were acting as a Trojan horse for armed insurgent movements.
The accusations came after opposition leader Bulcha Demeksa complained about widespread arrests and harassment in the Oromia region in the southern central part of the country.
Mr Meles said the government was aware that some senior leaders of opposition organisations were members of the rebel Oromo Liberation Front (OLF).
He said once the government had enough evidence the culprits would be arrested and put on trial.
Another opposition leader accused the government of ignoring issues in the Ogaden region despite allegations of human rights abuses in the international media.
In response, Mr Meles poked fun at media coverage of recent Ogaden National Liberation Front (ONLF) claims that the rebels had besieged his political adviser.
As he had been with the adviser at the time, Mr Meles inquired why he had not been surrounded too.
However, he said nothing about rebel claims of heavy fighting in the past few days.
The ONLF says up to 250 government troops died in a battle on Sunday.
On Monday, a government spokesman said any skirmishes may have involved local, pro-government militias, not the army.