On Thursday, the demonstrators cut power at Bangkok's police headquarters and asked police to join their side.
The demonstrations that started Sunday have raised fears of fresh political turmoil and instability in Thailand and pose the biggest threat to Yingluck's administration since she came to power in 2011.
The protesters accuse Yingluck of serving as a proxy for her billionaire brother Thaksin Shinawatra—a former prime minister who was ousted in a 2006 military coup but retains strong support from the rural majority in Thailand.
Thaksin, who lives in Dubai to avoid serving a jail term for a corruption conviction he says was politically motivated, is a highly polarizing figure in Thailand.
So much so, that an ill-advised bid to push a general amnesty law through parliament—which would have paved the way for his return—sparked the latest wave of protests earlier this month.
Crowd sizes peaked Sunday at over 100,000 and have dwindled in recent days to tens of thousands, but organizers are calling for bigger crowds over the weekend.
Protest leader Suthep Thaugsuban, who resigned as an opposition Democrat Party lawmaker to lead the protests, says he will not negotiate.
He says his goal to rid the country of Thaksin's influence.
