Vice President Mike Pence will announce new US sanctions against Venezuela and call for a "sham" May election to be delayed.
The vice president "will announce new Venezuela kingpin sanctions and call to suspend (president Nicolas) Maduro's sham elections," an official told AFP.
Pence's address is expected to focus, in part, on holding "undemocratic actors" accountable.
The OAS has been deadlocked between members keen to punish Venezuela for democratic backsliding, and long-standing Maduro allies who want to prop up the regime.
Amid swelling international criticism, Venezuela in April 2017 announced its withdrawal from the OAS, which it accuses of interference. The process will take two years.
A Pence aide said they expect the Venezuelan delegation to walk out during his speech.
Pence's address comes two weeks before a divisive presidential poll in Venezuela, scheduled for May 20.
The vote is being boycotted by the opposition and branded illegitimate by much of the international community.
US lawmakers are calling on the Trump administration to take a harder line on Maduro's regime.
US Senator Marco Rubio has gone as far as calling for Washington to press for regime change.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)