Opponents of President Nicolas Maduro are preparing to take to the streets Wednesday in what they've dubbed the "mother of all marches" against Venezuela's embattled socialist leader.

Security forces have fired tear gas and rubber bullets to block at least five previous attempts by demonstrators to reach downtown Caracas. At least five deaths and hundreds of arrests have been blamed on the response to paralyzing protests that were triggered by the Supreme Court's shock decision three weeks ago to strip the opposition-controlled legislature of its last remaining powers.

Maduro late Tuesday accused the U.S. State Department of trying to promote a military intervention. He's expected to address supporters at a rival march.

The State Department and several regional governments have deplored excessive violence by security forces and pro-government groups.