Aljazeera reported the toll rose to 36 after the second day of protests against the new fuel prices.
A statement issued by the ruling Popular National Congress said 30 people were killed and scores injured.
Some agencies put the toll as high as 39, including members of the Yemeni security forces, with 50 people injured.
The protests in the capital, Sanaa, have spread to Aden, Hedida and other cities.
On Friday morning, protests had calmed in the capital and at least six other towns, but there were fears they would resume later in the day.
Army tanks, which were called in to reinforce the police, were seen stationed around government buildings, while tight security measures were also visible around the residences of high-ranking officials.
The loss of subsidies on petrol will
cut into people's meagre income
A cabinet statement, said the government had concluded that the continuation of subsidising fuel products would eventually lead to an increase in the budget deficit and put pressure on exchange rates and prices. Therefore, the government would maintain high oil prices.
Officials argued the budget deficit would plunge to 13% if fuel prices were cut.
Opposition parties have suspended dialogue with the ruling party until it reconsiders what they describe as unfair government measures.
Yemeni Civil Service Minister Hamoud Khalid al-Soufi denied the fuel price increases would have a negative impact on the people's interests.
"On the contrary, the revenue from these hikes have been allocated for increasing salaries and social security services," al-Soufi told Aljazeera.
Al-Soufi said the demonstrations
were a form of free expression
He said the demonstrations in Yemen were not protests but a way by which the people were able to express their views.
But he said some people took advantage of the demonstrations and attacked institutions and destroyed cars.
Commenting on the spread of protests, the Yemeni minister said only a small group of people infiltrated under the cover of night to Aden to set fire to some petrol stations.
Yemen, situated at the southeastern tip of the Arabian peninsula, has a population of 19.7 million, and per capita gross domestic product is less than $800. It is one of the poorest countries in the world.
Despite being a crude exporter, Yemen still imports about 60% of diesel and 9% of benzene for local consumption.