DAMASCUS (AFP) - President Bashar al-Assad said on Monday dialogue could lead to a new constitution and even the end of his Baath party's monopoly on power, but he refused to reform Syria under "chaos." His remarks were condemned by pro-democracy activists who vowed that the "revolution" - now in its fourth month - must go on while Washington called for "action not words." US State Department spokeswoman Victoria Nuland said: "What is important now is action, not words. A speech is just words." European foreign ministers agreed to beef up sanctions on the embattled president over his regime's deadly crackdown on protests, with some calling on him to reform or "step down." Assad acknowledged in his televised speech that Syria had reached a "turning point." He said dialogue was under way that could lead to a new constitution and raised the possibility of elections and an end to the ruling Baath party's dominance, a key opposition demand, while warning the economy was on the verge of collapse. "We can say that national dialogue is the slogan of the next stage," Assad said. "The national dialogue could lead to amendments of the constitution or to a new constitution." Reform was "a total commitment in the interest of the nation," he added in his third speech to the nation since the protests began. Assad offered condolences to the families of "martyrs" from the unrest rocking the country since mid-March, but said there could be "no development without stability, no reform in the face of sabotage and chaos." "We make a distinction between those (with legitimate grievances) and the saboteurs who represent a small group which has tried to exploit the goodwill of the Syrian people for its own ends," he said. Witnesses and opposition activists said the speech was followed by protests in the northern city of Aleppo, in the flashpoint province of Idlib in the northwest, the central regions of Homs and Hama and in Damascus suburbs. "The protesters condemned the speech which branded them as saboteurs, extremists," the head of the London-based Syrian Observatory for Human Rights, Rami Abdel Rahman, told AFP by telephone. "The demonstrators are calling for freedom and dignity." Abdel Rahman said 60 demonstrators in Aleppo were arrested over the past 24 hours. According to his group, the violence has so far claimed the lives of 1,310 civilians and 341 security force members. Opposition activists said Assad's speech failed to specify concrete steps - namely the pullout of troops from besieged cities - and only deepened the crisis. The Coordination Committee, an umbrella group of activists, called for "the revolution to carry on until all its aims have been achieved." "We consider any dialogue useless that does not turn the page on the current regime," it said in a statement received by AFP. Prominent human rights lawyer Anwar al-Bunni, who was freed from five years in prison last month, called Assad's speech "disappointing." "The key demands made by the people were not mentioned and the existence of a political crisis has been ignored," he said. British Foreign Secretary William Hague said on Twitter Assad's speech was "disappointing & unconvincing." "Little new on how reforms will be implemented & when, or how he will end violence," he tweeted. Meanwhile, as International Committee of the Red Cross chief Jakob Kellenberger began a two-day trip to Syria, the authorities took diplomats and journalists to what they said was the site of a mass grave of people killed by "armed groups." The third such "mass grave" near the restive northern town of Jisr al-Shughur, the focus of military operations since June 12, contained at least 29 bodies, a Syrian military source told AFP.