Cesare Battisti, a former Italian communist activist sought by Rome for four murders in the 1970s, will be extradited to his home country "in the coming hours", the Italian government said on Sunday.

Battisti, who has been sentenced to life in prison, was arrested on Saturday after an international police squad tracked him to Bolivia.

He was convicted in 1979 of belonging to the Armed Proletarians for Communism, an outlawed leftist group.

The communist activist lived in Brazil for years under the protection of former leftist President Luiz Inacio Lula da Silva (2003-2010), who is now in prison for corruption.

"Italian terrorist Cesare Battisti was detained in Bolivia (Saturday night) and will be soon brought to Brazil, from where he will probably be sent to Italy to serve a life sentence," tweeted Filipe G Martins, a senior aide on international affairs to Brazilian President Jair Bolsonaro.

During Brazil's recent presidential campaign, the far-right Bolsonaro, who took office on January 1, vowed that if elected he would "immediately" extradite Battisti to Italy.

In mid-December, Brazil's outgoing president, Michel Temer, signed an extradition order for Battisti after a judge ordered his arrest. By then the Italian had disappeared.

Battisti, 64, was arrested late on Saturday in the Bolivian city of Santa Cruz de la Sierra, Brazilian police sources told Brazilian media. Italian interior ministry sources confirmed the arrest.

"Battisti was arrested in the street, unarmed and he didn't resist, responded to police in Portuguese and showed a Brazilian document confirming his identity," an Italian interior ministry source said. "Now Italy is waiting for him."

Italian state police said the arrest had been carried out by a joint team of Italian and Bolivian officers with the help of Italy's "counterterrorism" section.

'Little gift'

Italy's Interior Minister Matteo Salvini thanked the Italian and foreign police who captured "a delinquent who did not deserve the comfortable life on the beach, and who should spend out the rest of his days in prison".

Bolsonaro's legislator son, Eduardo Bolsonaro, tweeted in Italian with a picture of Battisti: "Brazil is no longer the land of bandits. Matteo Salvini, the 'little gift' is on its way."

Battisti escaped from an Italian prison after being convicted in 1979 of his allegiance to an outlawed leftist group, Armed Proletarians for Communism.

He was subsequently convicted in absentia of having killed two Italian policemen, taking part in the murder of a butcher and helping plan the slaying of a jeweller who died in a shooting which left his 14-year-old son in a wheelchair.

Battisti admitted to being part of the group but refused to take responsibility for any deaths.

He reinvented himself as an author, writing a string of noir novels and in 2004 skipped bail in France, where he had taken refuge. He went to live clandestinely in Brazil until he was arrested in 2007 in Rio de Janeiro.

After years in custody, then-President Lula issued a decree - later upheld by Brazil's Supreme Court - in 2010 refusing Battisti's extradition to Italy, and he was freed, angering Italy.

Battisti, who has a five-year-old Brazilian son, last year told the AFP news agency that he faced "torture" and death if he were ever to be sent back to Italy.