Spain's King Felipe VI begins a new reign Thursday already facing a threat to the unity of his kingdom as the northeastern region of Catalonia fights to hold an independence referendum on November 9.

With only a ceremonial role in Spain's parliamentary democracy, the new king, a tall 46-year-old former Olympic yachtsman, has limited capacity to mend all the woes of a country suffering high unemployment and longstanding separatist tensions.

Juan Carlos I, who gave up the Spanish crown Wednesday aged 76, led Spain to democracy and foiled a military coup, winning widespread respect that later crumbled under royal scandals.

The abdicating king played a determining role in Spain's modern history when he stepped up as the first crowned head of state in 44 years after the death of General Francisco Franco.

A teary-eyed King Juan Carlos sealed his abdication of the Spanish crown on Wednesday after a four-decade reign, clearing the throne for his 46-year-old son, Felipe VI.

The 76-year-old monarch signed the act of parliament ending his reign with a golden pen at a ceremony in Madrid's Royal Palace, then hugged his son, who will be sworn in on Thursday morning.

King Juan Carlos formally abdicates on Wednesday, ending his 39-year reign, in a Madrid bedecked with flags and flowers to hail his son and successor Felipe VI.

The 76-year-old Juan Carlos, who led Spain from dictatorship to democracy but was later hurt by scandals, steps down in a short, solemn ceremony in the late afternoon at Madrid's old Royal Palace before 150 guests.

Plates, key rings and fridge magnets with the smiling faces of Spain's king-to-be Felipe VI and his queen Letizia are filling giftshops ahead of their enthronement on Thursday.

Souvenir stores are stacked with mugs and T-shirts that are already proclaiming them the "King and Queen of Spain", even though they have not been crowned yet.

Spain's Senate voted massively in favor of King Juan Carlos's abdication Tuesday, clearing the path for his son Felipe to take the scandal-tainted crown in the first royal succession of the post-Franco era.

Despite smoldering pro-Republican sentiment, the upper house Senate voted 233-5 in favor of the abdication law, with 20 abstentions.

As thousands celebrate Spanish King Felipe VI's enthronement Thursday, his sister Cristina will be notably absent. When the guests disperse, the cloud of scandal over her and the family will stay.

The smiley blonde Cristina, 49, is not invited to the party for the succession, since she is at the center of the corruption scandal that partly prompted it.

Spanish police arrested eight people in pre-dawn raids in Madrid on Monday against a jihadist recruitment network led by a former Guantanamo Bay inmate, the government said.

Police have so far launched 12 raids in the Spanish capital, detaining eight people, and the investigation remains open, Spain's interior ministry said in a statement.

A Madrid court jailed a member of armed Basque separatist group ETA for 29 years on Monday for the killing of a Spanish soldier in 1995.

Juan Ramon Carasatorre Aldaz, 52, was sentenced to 29 years for the killing of infantry brigadier Mariano de Juan Santamaria, who was shot in the head on April 10, 1995, in the northern city of San Sebastian, the court said in a ruling Monday.

Spanish police arrested eight people in pre-dawn raids in Madrid on Monday against a jihadist recruitment network led by a former Guantanamo Bay inmate, the government said.

The cell found and dispatched recruits for Islamic State of Iraq and the Levant (ISIL) militants based in Syria and Iraq, Spain's interior ministry said in a statement.