Hundreds of migrants, which the United Nations says are people mainly from Haiti and Venezuela who had lived in Chile but are now trying to leave, have been blocked for weeks at the border between the Peruvian city of Tacna and Arica in northern Chile.

Many say they are seeking to make their way home, or continue further north to the United States, as Chile tightens migration controls.

The Peruvian government has already sent 200 police officials to reinforce immigration control points in what it said was also a bid to limit transnational crime.

On Wednesday, President Dina Boluarte said extra soldiers will be deployed to support police at border crossings with Chile, Bolivia, Brazil, Ecuador and Colombia.

"The national police will maintain control of internal order with the support of the armed forces," she told journalists.

The government did not say what the state of emergency would entail, or how long it would remain in place.