As many as 10 people were killed on Thursday during fresh fighting between protesters and government forces in Yemen.
Officials said heavy battles were raging across the capital Sanaa, as demonstrators continued to call for an end to the 33-year rule of President Ali Abdullah Saleh.
Gun battles took place near the so-called “Change Square”, a street that demonstrators have overtaken and renamed.
The renewed fighting came as aid agencies warned that Yemen is on the verge of a humanitarian crisis.
“We’ve seen senior officials suggesting that if there’s a political settlement in Yemen, this will unlock a large increase in international aid. But we cannot wait, because ordinary people are suffering now,” said Oxfam’s Richard Stanforth.
“Money was found very quickly for Libya, Tunisia and Egypt. Yemen was forgotten,” added Stanforth, Regional Policy Officer for the Middle East.
According to the United Nations Children’s Fund, rates of malnutrition in Yemen are among the highest in the world, especially from communities displaced by the violence.
Aid agencies warned on Thursday that vaccination programmes were under threat from fuel shortages and that outbreaks of deadly diseases were likely.
Saleh was treated in a Saudi Arabian hospital in June following an assassination attempt.