New Delhi, Feb. 12 -- Argentina's Senate early Thursday gave its overall approval to a labor overhaul that is considered crucial to President Javier Milei's shock therapy program after hours of debate that unfolded in the shadow of a mass protest outside Congress.

Thousands of workers mobilized by powerful trade unions converged on a central square of downtown Buenos Aires earlier Wednesday, blocking traffic and clashing with police as the marathon session got underway.

The fiery standoff underscored the sensitivity of labor rights in this nation dominated since the 1940s by Peronism, a populist movement that has swung right and left ideologically, but has always claimed to champion workers' rights.

At around 1:30 a.m., senators backed...