Syria says it will only use chemical weapons against a foreign attack and never on its own people.

Foreign Ministry spokesman Jihad Makdissi said Monday during a news conference that the military is securely guarding the nation's chemical weapons stockpile.

Rights activists said fighting between rebels and government troops continued Monday in the capital, Damascus, and in the northern city of Aleppo.

The clashes came as the European Union further tightened sanctions against Syria, strengthening an arms embargo, blacklisting nearly 30 people and companies associated with the regime, and banning the Syrian national airline from landing in EU countries.

Meanwhile, Arab leaders are promising Syrian President Bashar al-Assad safe passage if he agrees to leave the country.

At an emergency meeting Sunday in Doha, Arab League foreign ministers called on Mr. Assad to step down, but gave no details about where he could settle. They also pledged $100 million to help Syrian refugees.

Sunday, U.N. Secretary-General Ban Ki-moon said almost 17,000 people have been killed since the uprising against Mr. Assad's rule began in March of last year.

The death toll given by Mr. Ban is a sharp increase from previous estimates given by the United Nations, which for several months has said that at least 10,000 people have been killed in Syria.