Syrian President Bashar al-Assad says “saboteurs” are trying to exploit calls for change and he warned there can be no national reform through “vandalism.”

The 70-minute speech at Damascus University Monday was his third major address since anti-government protests began in mid-March.

Witnesses and activists say protests erupted in several places after Mr. Assad's speech, including the flashpoint province of Idlib and the central cities of Homs and Hama. The protesters condemned the speech and called for the Syrian president to leave.

Mr. Assad told the nation he is forming a committee to study reforms to Syria's constitution, including one that could give political power to parties other than the ruling Ba'ath party. He also warned the country faces the “weakness or collapse” of its economy.

U.S. State Department spokeswoman Victoria Nuland said Monday the U.S. demands “actions, not words” from the Syrian leader.

The French news agency spoke with refugees at the Turkish border who reacted angrily to the speech.

Turkey is sheltering more than 10,000 Syrians in tent cities near its border with Syria. They fled Syria's military crackdown on dissent.

Rights activists say that nationwide, more than 1,400 civilians have been killed and 10,000 have been detained since mid-March in the government's crackdown on protests.

Before Monday's speech, British Foreign Secretary William Hague called on Mr. Assad to either reform or step aside. Hague said he hoped Turkey would pressure neighboring Syria and tell Mr. Assad he is “losing legitimacy.”

In a speech two weeks after the protests began, Mr. Assad said foreigners had created a conspiracy to bring down his government. In mid-April, he said the government would abolish the 50-year-old emergency law and that he was urging his Cabinet to consider measures to create new jobs.