As the Europe Commission stands by the Spanish government\u0026#039;s efforts to quash Catalonia\u0026#039;s independence referendum, the U.N. human rights chief is demanding an investigation into allegations of abuse by state police forces as the regional government is launching its own investigation into violence that left nearly 900 people injured this weekend.\u0022With hundreds of people reported injured, I urge the Spanish authorities to ensure thorough, independent, and impartial investigations into all acts of violence,\u0022 Zeid Ra\u0026#039;ad Al Hussein, U.N. High Commissioner for Human Rights, said in a statement released Monday.Madrid, which has maintained that the referendum violates Spain\u0026#039;s constitution, sent additional police forces into the region ahead of the vote to seize ballot materials and close down polls, triggering massive protests and occupations of polling stations by voters.The people of Catalonia, a wealthy northeast region of Spain, voted overwhelming in favor of independence on Sunday despite efforts by the Spanish government to prevent the referendum.\u0022Thousands of Spanish police were shipped in to the region to prevent the vote on secession,\u0022 Reuters reports, \u0022though scenes of violence due to heavy-handed tactics by armored, baton-carrying riot units have received international condemnation.\u0022The U.N. commissioner, who said he was \u0022very disturbed by the violence,\u0022 urged leaders from Madrid and Catalonia to resolve the independence dispute \u0022through political dialogue, with full respect for democratic freedoms,\u0022 and called on the Spanish government \u0022to accept without delay the requests by relevant U.N. human rights experts to visit.\u0022Amnesty International has deployed a team of researchers in Catalonia to monitor human rights violations. John Dalhuisen, the group\u0026#039;s\u0026nbsp; Europe and Central Asia director, said: \u0022There is plenty of footage to suggest that police officers have used excessive and disproportionate force at at least some of them. With tensions running high, it is essential that both Spanish law and international human rights law is respected.\u0022Carles Puigdemont—the Catalan leader who was inaugurated as president after a reported 90 percent of voters expressed support for Catalonia\u0026#039;s independence—announced on Monday that Catalonia will launch a special commission to investigate alarming actions by Spanish national police, which were documented and widely shared on social media throughout the weekend.The violence towards #SpanishPolice shows why filming Gardai should be illegal.#CatalanReferendum #Jobstown #cblivepic.twitter.com/EILXrX7TpV— The Labour Parody (@Iab0ur) October 2, 2017What the Spanish authorities describe as \u0022proportional and professional actions of the police\u0022 #CatalanReferendum pic.twitter.com/7ImP14GstU— Thomas Moens (@TMoens) October 1, 2017Spain\u0026#039;s National Police brutalize voters in Catalonia polling center (a school) today in an attempt to suppress #CatalanReferendum vote. pic.twitter.com/jh4xA8u8Bb— WikiLeaks (@wikileaks) October 1, 2017Puigdemont said in a news conference that the vote was valid and binding, but that he had not yet been in touch with the Spanish government. Although he had previously promised to \u0022declare Catalan independence imminently,\u0022 Puigdemont said on Sunday night that \u0022the referendum results would be put before the regional parliament \u0026#039;where the sovereignty of our people lies, so that it can act in accordance with the law of the referendum,\u0026#039;\u0022 the\u0026nbsp;Guardian\u0026nbsp;reports.The Catalan leader called on Spanish Prime Minister Mariano Rajoy to declare whether he would engage in mediation talks overseen by the European Union to transition the region to an independent nation.However, in a statement released Monday, the European Commission, the executive of the European Union, endorsed Madrid\u0026#039;s claim that \u0022under the Spanish Constitution,\u0022 the vote for Catalan independence \u0022was not legal.\u0022\u0022For the European Commission, as President [Jean-Claude] Juncker has reiterated repeatedly, this is an internal matter for Spain that has to be dealt with in line with the constitutional order of Spain,\u0022 the statement continued, adding: \u0022We trust the leadership of Prime Minister Mariano Rajoy to manage this difficult process.\u0022On Sunday, Rajoy was rebuked for praising the actions of the Spanish police forces and refusing to condemn the violence that left hundreds of Catalan voters injured.