Tens of thousands of people have flooded the streets of the Yemeni capital Sanaa, again voicing their demands for the fall of the government.
Protesters shouted "Leave!", signalling their rejection of an offer made by President Ali Abdullah Saleh on Monday to form a new unity government.
Mr Saleh has blamed the US and Israel for the unrest in Yemen and elsewhere.
He has faced daily protests inspired by the overthrow of the governments in Tunisia and Egypt.
"The events from Tunisia to Oman are a storm orchestrated from Tel Aviv and under Washington's supervision," President Saleh told reporters in Sanaa, according to AFP news agency.
"What is taking place on Yemen's streets is just a copycat attempt, as Yemen is not Tunisia or Egypt and the Yemeni people are different," he said.
Analysts say the remarks are the harshest criticism yet of Washington from the man who has been an ally in the US campaign against al-Qaeda.
Meanwhile, five provincial governors have been sacked, according to a government official.
The reason for their dismissal is not clear, but AFP news agency reports that three of them had criticised Mr Saleh's crackdown on protests.
On Monday, Mr Saleh offered to include members of the opposition in his government in return for an end to the protests.
But the gesture did little to placate protesters, thousands of whom gathered not only in Sanaa but in other Yemeni cities including Taiz, Ibb and al-Bayda governorate, according to the website of the Yemeni weekly Al-Masdar.
Key opposition parties joined the demonstrations for the first time in what organisers declared to be the largest turnout yet.
In Sanaa, a crowd of several thousand supporters of President Saleh held a counter demonstration.
Anti-government demonstrators said they called Tuesday's "day of rage" in response to the deaths of anti-government "martyrs" during protests, particularly in the southern port city of Aden.
Troops fired on demonstrators in that city at the end of last week, killing four, according to officials quoted by Associated Press news agency. However, human rights group Amnesty International said 11 people were shot dead.
Amnesty says the overall death toll in the recent protests has now reached 27, with 24 of the deaths occurring in Aden.
President Saleh, who has ruled since 1978, says he will stay on until elections in 2013, but will not run for another term.