A group of 50 countries supporting sanctions against Bashar al-Assad's Syrian regime on Tuesday issued a statement denouncing continued arms sales to Damascus.

After meeting in Paris, the countries expressed "strong disapproval of any financial or other support, in particular the continuation of arms sales to the Syrian regime", in a clear reference to Russia.

France's Alain Juppe plans has invited several of his fellow foreign ministers to talks in Paris on Thursday on ways to boost the pressure on Bashar al-Assad's Syrian regime, a government source said.

The official said the meeting and the guest list were not finalized, but that Juppe hoped to host around a dozen ministers, some of whom will be in the region already for NATO talks in nearby Brussels on Wednesday and Thursday.

Anti-regime activists in Syria on Tuesday advised fellow citizens to be well prepared and have their facts ready ahead of a visit by a U.N. team set to tour the country to monitor a fragile ceasefire.

In messages posted on several Facebook pages, the activists listed 10 key points to keep in mind as the monitors prepare to visit several hot spots across the strife-torn country and speak to the local population.

WikiLeaks founder Julian Assange interviewed Hizbullah chief Sayyed Hassan Nasrallah on Tuesday in the debut of his "The World Tomorrow" talk show on Russia's state-funded RT cable broadcaster.

Assange remains under house arrest and was speaking from his study in London to Nasrallah at his Lebanese office via a computer video link.

A top Jordanian Salafist leader said on Tuesday eight Sunni jihadists have been arrested as they tried to cross the border into neighboring Syria to fight President Bashar Assad's forces.

"The Jordanian authorities have recently arrested eight jihadists as they attempted to go to Syria for jihad. They are currently in the Zarqa prison waiting for prosecutors to charge them," Abed Shehadeh, known as Abu Mohammad Tahawi, told Agence France Presse.

Advance team leader Colonel Ahmed Himmiche acknowledged on Tuesday that a hard-won U.N. military observer mission to oversee a Syria ceasefire will be "difficult."

"We need to move forward little step by little step," the Moroccan officer told reporters.

Syrian regime forces killed at least two civilians on Tuesday, as they kept up their bombardments of protest centers despite a warning by Washington that it is already discussing options in case a U.N.-backed peace plan collapses.

An advance team of U.N. military observers arrived in Damascus on Sunday to oversee a shaky ceasefire, but dozens of people -- troops as well as civilians -- have been killed since it went into force on Thursday, monitors said.

A U.N.-Arab League peace plan for Syria has only a three percent chance of working, the emir of Qatar said on a visit to Rome Monday, as a U.N.-backed ceasefire was marred by ongoing violence.

Sheikh Hamad bin Khalifa al-Thani told a press conference that the chances for success "are no higher than three percent", and that the Syrian people should not be supported through peaceful means but "with arms".

A German shipping firm on Monday dismissed reports one of its vessels was carrying Iranian arms bound for Syria in violation of EU sanctions against the regime of President Bashar al-Assad.

Respected news weekly Der Spiegel reported at the weekend that the ship, the Atlantic Cruiser, owned by German firm Bockstiegel but chartered by a Ukrainian firm, had been stopped on the high seas with Iranian weapons on board.

Syrian tribes opposed to the embattled regime of Bashar al-Assad said Monday they would join forces in an "Assembly of Tribes," Syrian opposition members and media reported.

"Today we proclaim, as children of all tribes, an Assembly of Tribes," opposition Syrian National Council (SNC) member Mahmut al-Maslat said in a statement read out on behalf of the assembly.