The leader of Catalonia has called for international mediation to resolve a standoff with the Spanish government, the day after hundreds of people were injured as police tried to forcibly disrupt a referendum on independence that had been ruled illegal.

Results showed voters had overwhelmingly backed independence in the referendum, which Spain has ruled illegal and which opponents of secession mostly boycotted.

The vote was valid and must be implemented, Catalan leader Carles Puigdemont said.

"It is not a domestic matter," he told a news conference. He said it was "obvious that we need mediation", adding: "We don't want a traumatic break ... We want a new understanding with the Spanish state."

Prime Minister Mariano Rajoy met leaders of other political parties and his conservative government issued a statement saying he was seeking a joint response to the crisis.

He also spoke to other European leaders and thanked them for supporting Spain's constitutional order, the statement said.

In Barcelona, hundreds of students gathered in a central square to protest at Sunday's police crackdown, chanting pro-independence slogans and waving Catalan flags.

The government crackdown had "provoked an unacceptable totalitarian situation using state violence," student Albert Lopez said.

Another protest was held later outside the headquarters of the Spanish National Police in Barcelona.

Elsewhere, life in the city returned to near normal, but the violence had clearly left people in shock and may have hardened attitudes among those who favour independence.

"There is no possibility of dialogue now with the government. We are clear on that," said a 51-year-old retired worker who declined to give his name.

Spain's wealthiest region, wedged in the northeast on the Mediterranean coast below the mountainous border with France, has its own language and culture, and a growing minority there have nurtured hopes of independence for years.

The central government says the constitution prohibits secession and is non-negotiable.

The crisis could deepen further if the Catalan regional parliament uses the vote as justification for a unilateral declaration of independence, as foreseen in the referendum law enacted by the region but rejected by Madrid.

With 95%of the vote counted, authorities said the "Yes" vote stood at 90.1%, on a turnout of 2.26 million out of 5.34 million registered voters.

Polls before Sunday's vote put support for secession at only around 40%, but most opponents were expected to boycott the vote.

The Spanish government has taken the risk that its violent crackdown could increase support for the secessionists.

Mr Puigdemont, who held the vote in defiance of a court order, urged Mr Rajoy to say whether he was in favour of mediation, which he said should be overseen by the European Union. He said Brussels had been timid and lacked courage on the matter.

An EU spokesman declined to say whether the Union would mediate, although it would be unusual for Brussels to take such a step within one of the bloc's own member states.

Other European leaders have mostly shied away from commenting on what they consider an internal matter, although some have expressed alarm at the violence.

Mr Rajoy held meetings with Pedro Sanchez, leader of the opposition Socialists, and centrist Albert Rivera.

Mr Rivera called on the prime minister to suspend Catalan autonomy and hold elections in the region to change the nationalist-led government there, something Madrid has not ruled out.

Mr Sanchez urged the prime minister, who takes a hard line against Catalan separatism, to start a dialogue with Mr uigdemont.

He disapproved of the police charges which left many injured yesterday, a Socialist Party statement said.

Why independence?

With its own regional parliament, Catalonia already enjoys significant powers over matters such as education, healthcare and welfare.

Spain's economic woes, coupled with resentment that the region pays billions of euro more in taxes than it receives from Madrid, have pushed secession from the fringes of Catalan politics to centre stage.

The regional government argues that an independent Catalonia would be richer and better able to protect its language and culture.

Read more: Key dates in Catalonia's push for independence

Taoiseach Leo Varadkar has said that Ireland respects the territorial unity of Spain and does not recognise the result from the referendum held in Catalonia at the weekend, but said violence is never justified.

Spain's two biggest trade union federations, the General Union of Workers (UGT) and Workers' Committees (Comisiones Obreras), distanced themselves from calls by pro-independence groups and trade unions in Catalonia for a general strike in the region on Tuesday.

Elsewhere in Spain, Catalonia's bid for independence is fiercely opposed and led to pro-unity demonstrations in many cities from Zaragoza to Madrid over the weekend.