The Syrian army is engaged in a "crucial and heroic battle," President Bashar Assad said Wednesday in a speech published by official media agency SANA on the occasion of the 67th anniversary of the army.

"The army is engaged in a crucial and heroic battle... on which the destiny of the nation and its people rests. The enemy is among us today, using agents to destabilize the country, the security of its citizens... and continues to exhaust our economic and scientific resources," he said.

Four Yemeni soldiers and a civilian were killed in an attack on Wednesday by al-Qaida militants on a police station in the southern town of Jaar, a local official said.

"Members of al-Qaida attacked the station with automatic weapons and hurled a grenade, killing two soldiers and a civilian," said the official.

Fighting between soldiers and rebels broke out on Wednesday for the first time near two Christian districts of Damascus, the Syrian Observatory for Human Rights said.

"Fighting erupted at dawn on Wednesday on the outskirts of the Bab Tuma and Bab Sharqi neighbourhoods. First indications are that one soldier has been killed," the Britain-based group said in a statement.

Israeli troops engaged in a brief exchange of fire with unidentified gunmen across the southern border with the lawless Egyptian Sinai Peninsula on Wednesday, a military spokeswoman said.

No-one was wounded in the exchange which took place shortly after troops arrested three "suspected infiltrators" sneaking across the frontier, she said.

A militant with the armed wing of Gaza's ruling Hamas movement died in Gaza City on Wednesday after the car he was travelling in exploded, Palestinian medical sources said.

There was no accusation against Israel, prompting suspicions it was a "work accident" -- the euphemism for the accidental detonation of explosives held by militants.

A wheelchair-bound Israeli who set himself alight over the spiraling cost of living died of his injuries, medics said on Wednesday, raising to two the number of Israelis who have died in such protests.

A spokesman for Tel HaShomer hospital near Tel Aviv said Akiva Mafi, 45, died of injuries sustained on July 22, in a development two days after the government voted through a harsh package of austerity measures likely to further hit the underprivileged.

A firefight between Yemeni security forces and gunmen dressed in police uniforms killed 15 people and wounded 43 at the interior ministry in Sanaa on Tuesday, medical and security officials said.

"The number of dead has increased to 15, in addition to 43 wounded," a medic said, while a security official confirmed the toll, saying it included one dead civilian.

More than 300 people, mostly civilians, were killed in the eastern Syrian province of Deir Ezzor in July, when army operations intensified, the Syrian Observatory for Human Rights said on Tuesday.

Activists recently posted videos showing gory images of bloody, mangled bodies, including women and children, and mutilated faces strewn across several city streets.

Tunisia's state of emergency has been extended by just one month, rather than the usual three, due to an improvement in the country's security situation, the president's office announced on Tuesday.

It is the sixth time the state of emergency has been extended since it came into force on January 14, 2011, when a mass uprising prompted veteran strongman Zine El Abidine Ben Ali to flee the country.

Israeli Prime Minister Benjamin Netanyahu said on Tuesday that he had not yet made any decision about a possible attack against Iran but reaffirmed his country's right to defend itself.

"I have not taken a decision" on any attack against Iranian nuclear facilities, Netanyahu said in response to a question during an interview with the private television Channel 2.