BEIRUT >> Gunmen assassinated an army general in Damascus today in the first killing of a high ranking military officer in the Syrian capital since the uprising against President Bashar Assad’s regime began in March, the country’s state-run news agency said.

The attack could be a sign that armed members of the opposition, who have carried out attacks on the military elsewhere in the country, are trying to step up action in the tightly controlled capital, which has been relatively quiet compared to other cities.

SANA news agency reported that three gunmen opened fire at Brig. Gen. Issa al-Khouli this morning as he left his home in the Damascus neighborhood of Rukn-Eddine. Al-Khouli was a doctor and the chief of a military hospital in the capital.

Capt. Ammar al-Wawi of the Free Syrian Army, a rebel group that wants to bring down the regime by force, denied involvement in the assassination, which came a day after two suicide car bombers struck security compounds in Aleppo.

Such assassinations are not uncommon outside Damascus and army officers have been killed in the past, mostly in the restive provinces of Homs and Idlib.

Violence in other parts of the country left at least 17 people dead as regime troops pushed into rebel-held neighborhoods in the central city of Homs and seized parts of the mountain town of Zabadani, north of Damascus.

The U.N. estimates that 5,400 people have been killed in Syria since the uprising began in March. But that figure is from January, when the world body stopped counting because the chaos in the country has made it all but impossible to check the figures. Hundreds are reported to have been killed since.

Syria’s turmoil began with peaceful protests against Assad’s rule, sparking the fierce regime crackdown. But it has since grown more militarized as army defectors and armed protesters formed the Free Syrian Army.

After Russia and China last weekend vetoed a Western and Arab attempt at the U.N. to pressure Assad to step down, the FSA’s commander said armed force was the only way to oust the president. Western and Arab countries are considering forming a coalition to help Syria’s opposition, though so far there is no sign they intend to give direct aid to the FSA.

Arab foreign ministers were to meet in Cairo on Sunday to decide their next step. An Arab League official said the ministers were likely to consider calling for a joint Arab-U.N. team of observers to be sent to Syria to investigate Assad’s adherence to past promises to halt the violence.

Damascus allowed in Arab League observers in December, but the mission was halted amid the accelerating bloodshed. The Syrians would be unlikely to accept a new observer team.

The ministers in Cairo also may discuss formally recognizing the main opposition Syrian National Council in a show of support, but such a step does not yet have full agreement among the ministers, the official said, speaking on condition of anonymity because he was not authorized to talk to the press.

Syrian Deputy Foreign Minister Faisal Mekdad warned that “he who bets on the collapse of Syria is betting on failure,” and said the government will “overcome difficulties” through its program of reforms and dialogue with opponents. The opposition has rejected the regime’s reform promises and offers of dialogue, saying they will settle for nothing less than Assad’s ouster.

Speaking to reporters in Damascus, he gave a vehement defense of the regime, denying it was shelling residential areas in Homs or other cities and laying out the state’s stance that it faces armed terrorists who reject attempts at reconciliation.

He denounced the Free Syrian Army as “reminiscent of criminals, drugs addicts and people who have come out of prison.” He said attacks by the group had killed 1,500 members of the military and security forces since March, and accused Arab countries of “encouraging armed groups to launch terrorist attacks.”.

Iranian President Mahmoud Ahmadinejad, one of Assad’s top allies, warned Arab countries today not to give aid to the opposition.

Speaking to tens of thousands of supporters in Tehran on the anniversary of the 1979 Islamic Revolution, Ahmadinejad said countries in the region that have never held free elections are trying to write a “prescription for freedom and elections for others” with the help of the United States.

“This is the most bitter and ridiculous joke of history,” Ahmadinejad said.

Today, Damascus gave Tunisian and Libyan diplomats 72 hours to leave the country, Foreign Ministry spokesman Jihad Makdissi told reporters. The move was in retaliation to the north African Arab nations’ eviction of Syrian ambassadors earlier this month.

For the past week, Syrian forces have been bombarding rebel-held neighborhoods in Homs, aiming to regain control of one of the main cities involved in the uprising. Activists say more than 400 people have been killed in the campaign.

Syrian troops shelled the Baba Amr district in Homs today, killing at least nine people, and another in the Bab Sbaa area, according to the Britain-based Syrian Observatory for Human Rights. Another activist group, the Local Coordination Committees said 15 people were killed in Baba Amr today.

The Observatory also reported that regime troops moved into parts of Zabadani, north of Damascus, after intense shelling and after rebel soldiers pulled back to spare residents’ property from further damage. Three people were killed in the bombardment, the group said.

Troops and rebel soldiers battled in Douma, a suburb of Damascus, said Mohammed Doumany, an activist there. The Observatory said troops stormed the Grand Mosque in Douma and detained a number of people who were inside.

The Observatory also reported a rare clash between troops and defectors late Friday in the northern Damascus neighborhood of Qaboun but had no details. It said troops shot dead an activist in the area.

In Idlib, where rebels control some areas, army defectors detonated roadside bombs and hand grenades against military vehicles near the village of Kfar Oweida Friday night, killing at least 10 soldiers, the Observatory said.