June 3 (Bloomberg) -- Bolivia's President Carlos Mesa called elections for a constituent assembly that will decide on calls for greater regional autonomy and changes to a hydrocarbon law, in a bid to end protests that have shut down the capital, La Paz, for the past two weeks.

``The country is going through a situation of high-risk confrontation, and I believe in this context, that we can't wait,'' Mesa said in a speech broadcast on Bolivian cable television station Bolivision. ``I hope this decision helps the country and puts an end to the uncertainty.''

A referendum will be held the same day on autonomy for Bolivia's southeastern lowland region of Santa Cruz, Mesa said. The assembly will decide the outcome on a date to be set by law, he said.

Thousands of protesters marched through the streets of La Paz and blocked highways leading into the capital with tree trunks, boulders and flaming tires to pressure for a constituent assembly, higher taxes on oil and gas output and nationalization of the hydrocarbon industry. State schools were closed and Congress postponed its sessions until June 7 as transport workers began a two-day strike.

Congress was scheduled to debate changes to a hydrocarbon law that adds a 32 percent tax to an existing 18 percent royalty on oil and gas production for 12 foreign companies operating in Bolivia, including Spain's Repsol YPF SA and Brazil's Petroleo Brasileiro SA.

To contact the reporter on this story: Alex Emery in Lima at aemery1@bloomberg.net

Last Updated: June 3, 2005 00:58 EDT