Walls of Yemeni streets are covered yet again with colorful paintings, but this time encouraging violence and calling for the death of Americans.

Hundreds of the pro Shia Houthi Movement slogan "Death to America," were painted in red and green in Sanaa adding a new entity to the wave of hatred against the US.

The Houthis are not your ordinary militant group. They run an army of 100,000 fighters, and six government wars against them from 2004-2009 made the movement ever more stronger.

The growing Shia influence in Yemen is also raising fears of Sunni neighbor Saudi Arabia. The Houthis control thousands of square kilometers near strategic border areas between both countries.

The slogan has been around for years but is now on the rise after a series of violent protests at the US embassy in Sanaa last week condemning the US produced movie offending Prophet Mohammed.