Ecuador's National Assembly passed a constitutional amendment to lift the limit on the country's presidential term, sparking violent clashes between protesters and riot police.
The amendment, which was approved on Thursday, prompted street demonstrations in Quito, the capital, against what many deemed a power grab by President Rafael Correa.
Part of a package of amendments, the measure will permit the leftist Correa to run for office indefinitely beginning in 2021. His current term ends in 2017 and he has said he does not intend to run at that time.
Analysts have called Correa's decision a shrewd political move considering Ecuador's current economic woes.
Outside the cordoned-off assembly, protesters who had been blocking major intersections with burning tyres grew in number after the vote passed.
Armed with sticks and rocks, some battled riot police, who responded with tear gas and batons.
There were no official numbers on injuries, but local media reported that some police and protesters had been wounded.
Street clashes were also reported in other cities.
Popular for generous social spending since first taking office in 2007, Correa has in recent months been forced to drastically cut back on spending and impose new taxes after world prices for the country's oil plunged.
Since June, Correa has faced mounting demonstrations by a wide spectrum of forces, including labour unions, indigenous groups, and the traditional conservative opposition.
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Beyond lifting the limit on presidential terms, the amendments remove collective bargaining for public employees, put the military in charge of domestic security, and declare communications a public service.
Human rights activist groups have criticised Correa for using his monopoly across all branches of government to stifle dissent, and they fear the latter measure will even further restrict freedom of expression.