Yemeni security forces fired tear gas and live rounds on Monday to break up a demonstration in Taez, south of the capital, killing two protesters and injuring dozens, witnesses and a medic said.
The security forces moved to disperse a sit-in which had overnight blocked the main road in Taez, firing tear gas and live rounds, witnesses said.
A medical official said the body of a protester shot dead was taken to the local hospital while dozens of injured people were admitted. The dead man was named as Mohammed Abdelhaq, 35.
Witnesses and the medic said another demonstrator was later also shot dead in further clashes, as the toll of people wounded by gunfire rose to 15, including three in serious condition.
Security forces used live rounds and tear-gas canisters as well as water cannons, according to witnesses.
Thousands of teachers have been staging a sit-in outside the regional ministry of education offices in Taez, 250 kilometres (150 miles) from Sanaa, demanding better pay and postponement of final exams, protest organisers said.
Their action was joined by hundreds of anti-regime protesters who advanced from the city's "Freedom Square," where crowds had been staging a sit-in for the past several weeks.
Demonstrators set up tents on the main Jamal road, where they spent the night, residents said.
Two other demonstrators were killed on Sunday when security forces intervened to disperse the protest after crowds besieged the local education ministry office and blocked the road, the state news agency Saba said.
The official said seven policemen were wounded in the confrontation.
On Saturday, security forces shot dead two students at a demonstration in Al-Maafar, in Taez province, demanding a postponement of exams as courses have been interrupted by strikes since anti-regime protests erupted in January.
Taez, the second largest city in the impoverished Arabian peninsula state, has become a focal point for protests demanding the ouster of President Ali Abdullah Saleh, who has been in power since 1978.
More than 150 people have been killed in the unrest, as Saleh stalls a Gulf-brokered deal which calls for his departure in 30 days after handing power to his deputy.