The U.S. State Department urged “all parties in the Syria conflict to respect the sovereignty of Lebanon” after Syrian warplanes pounded earlier on Wednesday a house on the outskirts of the eastern border town of Arsal.

“We’re frankly not in a position to confirm this ourselves at the moment. But if in fact it is confirmed by the Lebanese side, it would represent the latest and most egregious violation of Lebanon’s sovereignty … in the Syrian conflict,” said State Department spokesperson Victoria Nuland.

As many as 600 Europeans have joined the rebels fighting government forces in Syria, according to a British study.

Jihadists from 14 European countries including France, Germany, Britain and the Netherlands are among those to enter the conflict, according to research published Tuesday by the International Center for the Study of Radicalization (ICSR) at King's College London.

A Tunisian Salafist who fought in Syria was arrested on Wednesday after defending jihad, or Islamic holy war, in a television broadcast, a justice ministry source said.

Abou Zeid Ettounsi was detained under an arrest warrant issued by the public prosecutor after appearing on a private Tunisian TV channel, which questioned him about Tunisians taking part in the Syrian conflict, the source added.

Syria's air force staged new strikes Wednesday on several rebel-held areas across the country, including Raqa in the north, Homs in the center and Damascus province, a monitoring group said.

"New air raids struck the city of Raqa," said the Syrian Observatory for Human Rights, three weeks after rebels seized total control of the provincial capital.

A Syrian regime newspaper on Wednesday slammed militant Palestinian movement Hamas and its leader Khaled Meshaal for breaking with Damascus, accusing them of giving up on resistance against Israel.

The report comes two days after Meshaal's re-election as head of Hamas's politburo for another four-year term.

Syria's Muslim Brotherhood may be President Bashar Assad's best-organized political adversaries, but they are also loathed by some dissidents who accuse them of trying to dominate the opposition, backed by funds from Qatar.

The accusations date back to the start of uprising against Assad, but came to a head on March 19 after the election of rebel prime minister Ghassan Hitto, with some activists saying his selection was "pushed" by the Brotherhood.

Syrian warplanes pounded on Wednesday a house on the outskirts of the eastern border town of Arsal.

The house belongs to a member of al-Awad family, the state-run National News Agency reported.

France has not decided whether to support the lifting of an EU arms embargo on Syria, its foreign minister said Wednesday, in a u-turn from its previous stance favoring the supply of weapons to the war-torn country's rebels.

"We have to give a response end of May. Until then, I can't tell you yes or no," Laurent Fabius said on BFM-TV, after being asked what position Paris would take over the renewal of the near two-year-old embargo.

Syrian President Bashar Assad accused Turkish Prime Minister Recep Tayyip Erdogan of not having said "a single word of truth" about Syria's conflict, in an interview with Turkish media posted on the web.

"Erdogan has not said a single word of truth since the beginning of the crisis in Syria," Assad told journalists working for Turkish television Ulusal and Aydinlik newspaper.

Gunmen opened fire at dawn Thursday on several Syrian tanker trucks in the northern city of Tripoli, injuring one person, the National News agency reported.

NNA said the gunmen attacked seven diesel tankers near the footbridge in the area of al-Tabbaneh, injuring Saleh Fares, who Voice of Lebanon radio (93.3) said was one of the trucks' drivers.