SANAA, Yemen -- Yemeni security forces opened fire on anti-government protesters on Tuesday, killing at least three amid rising international concern over the strategically located nation.
The United Nations Security Council was scheduled to meet later Tuesday to discuss the deteriorating situation in Yemen, where rights groups say two months of protests calling for the president to step down have claimed 120 lives.
A government delegation also headed to nearby Abu Dhabi, in the United Arab Emirates, for talks with the six-nation Gulf Cooperation Council over a proposal for President Ali Abdullah Saleh to transfer power to his deputy to end the crisis. The opposition held similar talks in Saudi Arabia Sunday.
Thousands of protesters were marching in the southern city of Taiz, a hotbed of anti-government activism, demanding the president's resignation when security forces opened fire.
The director of a city field hospital, Dr. Sadeq al-Shuja, said at least one was killed in the crackdown. Activist Nouh al-Wafi said earlier that four protesters were wounded including one who was in a very critical condition.
Protesters also gathered outside a security office, where seven of their colleagues have been detained, demanding their release.
Four other protesters were killed in demonstrations earlier this month.
Tens of thousands took to the streets in the capital Sanaa later in the day and thousands demonstrated in Aden, Ibb, al-Hudaydah and other cities where most of the shops were closed in support of the protesters.
The Sanaa protest turned violent when security forces opened fire, lobbed tear gas canisters, and stun grenades at the protesters as they tried to make their way to the capital's main thoroughfare. The protesters replied by throwing stones.
A medical official and an eyewitness said at least two protesters were killed, and five were in serious condition. They spoke on condition of anonymity for fear of retaliation.
Khaled al-Ansi, a protest organizer, said around 60 were injured by bullets or sharp objects. A number of those injured were policemen who joined the protesters, witnesses said.
An ambulance accompanying the protesters, carrying four female doctors, was seized by security forces and was taken away.
Al-Ansi threatened that if the ambulance and the doctors are not released, the protesters would storm the riot police's headquarters.
The U.N. children's fund said Tuesday that at least 26 children have been killed during the protests over the last two months. Most died of wounds from live ammunition during clashes between security forces and anti-government demonstrators, said UNICEF spokeswoman Marixie Mercado.
The country's opposition, inspired by the uprisings in Egypt and Tunisia, says nothing short of Saleh's immediate departure would end the unrest.
Yemen is the poorest country in the Arab world, and protesters are calling for steps to improve livelihoods and open up the country's restricted political life. The protests are the biggest direct challenge to Saleh's three-decades in power. His weak government has little control beyond the capital and has struggled to confront an armed rebellion in the north and a secessionist movement in the south.