U.N. Secretary-General Ban Ki-moon is urging the world body's Security Council to take “serious” action on Syria, where he says casualties from a 10-month-old opposition uprising have reached “unacceptable” levels.

Speaking Monday on a visit to Abu Dhabi, Mr. Ban also appealed to the Council to act in a “coherent” manner in resolving the Syrian crisis. Western powers have been pushing the Council for months to condemn the Syrian government's violent suppression of the uprising, but Russia and China have blocked such action.

Russia is a military ally of Syrian President Bashar al-Assad and insists that any Council action should target not just the Assad government but also the opposition movement demanding an end to his 11-year autocratic rule.

Mr. Ban also praised the Arab League for holding a dialogue with Mr. Assad and sending observers to Syria last month to check on the president's pledges to stop cracking down on opposition protesters and release detained activists. The U.N. chief said he hopes the Arab League will continue those efforts.

Syrian opposition activists have criticized the observer mission, saying the Syrian government is deceiving it and using the monitors as a cover to intensify security operations against the opposition.

A Syrian parliament member representing the central city of Homs defected to the opposition late Sunday, making the announcement from Cairo in an interview with the Al-Arabiya television network. Imad Ghalioun said Homs, a hub of the uprising, is in a state of “disaster” and its people have suffered major rights violations at the hands of pro-Assad forces.

In another sign of growing domestic pressure on Mr. Assad, prominent Syrian opposition group the Syrian National Council says it has reached an agreement to boost coordination with Syrian army defectors known as the Free Syrian Army. In a statement Monday, the SNC says it will cooperate with the Syrian rebels on issues such as accommodating new defectors within the rebel army.

The Syrian government blames the uprising on armed terrorists. Syrian state-run news agency SANA says terrorists shot and killed a Syrian brigadier general as he was driving to work Monday. SANA also says five security personnel were buried Monday after being killed in fighting with rebels in the Damascus countryside and the northeastern region of Deir el-Zour.

The United Nations says violence linked to the uprising has killed more than 5,000 people. Syria says “terrorists” have killed about 2,000 members of the security forces since the unrest began.