Yemen's embattled leader rejected demands that he step down, saying widespread demonstrations against his regime are unacceptable acts of provocation.

However, U.S.-backed President Ali Abdullah Saleh, in power for three decades, offered to begin a dialogue with the protesters. The proposal was quickly rebuffed as insincere by an opposition spokesman.

In another attempt to defuse anger, Saleh told a news conference that he has ordered troops not to fire at anti-government protesters, except in self defense. At least 11 people have been killed since protests erupted earlier this month, including a youth shot dead Monday, medical officials said.

Despite Saleh's gestures, protesters are digging in. Several hundred camped overnight in a square in the capital of Sanaa, near the city's university. Similar to the scenes in Tahrir Square in Cairo, the epicenter of the Egyptian uprising, protesters in Sanaa pitched small tents and set up a platform equipped with loudspeakers. Protesters guarded access roads and searched those entering the square, AP reports.