Liberian President Ellen Johnson Sirleaf has tightened security in Monrovia, following violent demonstrations Tuesday.

The president instructed police to arrest and prosecute the instigators of the protests by former government soldiers demanding back pay.

Mrs. Sirleaf also banned street sales of gasoline in bottles and made it illegal to carry machetes at night in the capital.

The protesters threw rocks and vandalized vehicles outside Liberia's Defense Ministry, forcing U.N. peacekeepers to shoot in the air and fire teargas to disperse them.  

The demonstrations caused shops to close and civilians to desert the streets.

The former soldiers were demanding salaries for their service during Liberia's long civil war, which ended in 2003.

The Liberian government has largely demobilized the former army and has begun to create a new military as the country tries to rebuild from 14 years of devastating civil war.

Some information for this report was provided by AFP and Reuters.