SANAA: Yemeni security forces opened fire on anti-government protesters in the second largest city on Tuesday, killing at least one, activists and medics said 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 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 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.

Earlier this month, another four protesters were killed in the southern city.

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 cites where most of the shops were closed in support of the protesters.

The UN 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.