At least three people have died in clashes in Yemen as anti-government forces enter their second week of demonstrations, demanding the immediate resignation of President Ali Abdullah Saleh.

Two Yemenis were killed in the port city of Aden after police fired their weapons in an effort to move protesters along, according to media reports.

There were also reports that in Aden people burned a council building and police station to the ground.

Another person was killed and eight injured in the city of Taiz after a grenade was tossed from an speeding automobile onto a crowd of demonstrators.

The capital city of Sanaa witnessed violent street clashes between opponents and supporters of Saleh. Police reportedly fired shots into the air and launched tear gas.

Saleh, who has been president for 32 years, made some concessions recently to try to head off the revolt, but clearly that has not been enough to appease his opponent.

Among other measures, he vowed he would not to run for re-election and would not hand over the presidency to his son.

Yemen is the poorest country in the Arab world, with a rapidly expanding population, high unemployment and few natural resources.

The US embassy in Sanaa said it has seen a disturbing rise in the number and violence of attacks against Yemeni citizens at rallies and that these attacks were contrary to the commitments that President Saleh has made to protect the right of Yemeni citizens to gather peacefully to express their views.

Further, the embassy urged the government to prevent any further attacks on peaceful demonstrations and to ensure that all Yemenis, both pro and anti-government, have equal rights to speech and assembly.