BRUSSELS (AFP) - The European Union tightened economic sanctions on Syria on Thursday, ramping up international pressure while civilian opposition and army rebels agreed to team up against the regime. As the Syrian Observatory for Human Rights reported at least eight more civilians killed Thursday in the troubled provinces of Hama and Homs, UN rights chief Navi Pillay said the death toll since the protests broke out in mid-March was at least 4,000 and probably many more. EU foreign ministers met with Arab League secretary general Nabil al-Arabi in Brussels, hoping he would agree to join forces in order to form a united front against President Bashar al-Assad's crackdown on dissidents.Renewing their call for Assad to step aside and enable a democratic transition, the ministers warned that the violent repression risked taking Syria down "a very dangerous path of violence, sectarian clashes and militarisation." They urged Damascus to ease the suffering of the population in flashpoint towns, notably in the Homs region, by allowing "unhindered and sustained access to humanitarian agencies and workers" and ensuring that basic services work. The EU slapped a 10th round of sanctions on the regime, adding bans on exporting gas and oil industry equipment to Syria and trading Syrian government bonds in an effort to choke off funding. Ministers also agreed to refrain from providing concessional loans to Syria -- credit at lower rates and longer grace periods than offered by the markets. And European companies are barred from selling software that could be used to monitor Internet and telephone communications. The EU also added 12 more individuals and 11 more entities to a blacklist of people and companies hit by assets freezes and travel bans, diplomats said.