The destruction of Syria's chemical weapons arsenal will not be completed before a June 30 deadline agreed after Washington threatened air strikes last year, U.N. chief Ban Ki-moon has said.

An April 27 deadline for Syria to hand over its chemical weapons to international monitors also expired with Damascus holding around eight percent of its declared material.

Desperately needed medicines and medical supplies have reached the besieged Syrian town of Douma for the first time in a year and a half, the World Health Organization said Wednesday.

The United Nations' health agency said two of its trucks loaded with medical supplies had been part of an aid convoy that reached the rebel-held town in the Eastern Ghouta area of Damascus province on Saturday.

Syria's opposition National Coalition welcomed a pledge from U.S. President Barack Obama on Wednesday to ramp up support for rebels fighting the Damascus regime of Bashar Assad.

"This additional support highlights the partnership between the United States and the Syrian people in ending the humanitarian disaster and putting Syria on the path to genuine democratic transition," the bloc's U.S. representative, Najib Ghadbian, said in a statement.

New extremist networks in Europe and the Middle East may emerge from the war in Syria as thousands of foreigners fight alongside local militants, the U.N. Security Council heard Wednesday.

A report from the U.N.'s al-Qaida sanctions committee raised specific fears of large numbers of al-Qaida affiliated foreign fighters teaming up with Syria's branch of al-Qaida, Al-Nusra Front.

President Barack Obama mounted a defiant defense of his global leadership Wednesday, rebuking critics who see him as weak but warning that not every global threat justifies a U.S. military response.

In a major speech at the West Point military academy, Obama denied U.S. power had ebbed under his watch, after he withdrew troops from Iraq and as he does the same in Afghanistan.

The death toll from Syrian air raids on rebel-held areas in the northern city of Aleppo has topped 40 over a 24-hour period, a monitoring group said Wednesday.

Barrel bombs killed 22 people Tuesday in the eastern districts of Hay Qataneh, Tariq al-Bab, Bustan al-Qasr, Bani Zeid, Mghayer and Lairamoun, the Syrian Observatory for Human Rights said.

Syrian President Bashar Assad's is preparing for an inevitable re-election next week as the civil war shifts in the army's favor, with rebels losing ground and world powers paralyzed by divisions.

A brutal three-year conflict that wrought destruction across the country and displaced millions, has left large swathes of territory in rebel hands. And the June 3 vote, in which Assad is seeking a third seven-year term, will only take place in regime-controlled areas.

Foreign Minister Jebran Bassil noted on Wednesday that Lebanon has suffered the most from the repercussions of the Syrian crisis, most notably with the flow of refugees.

He said during the 17th meeting of the Non-Aligned Movement in Algeria: “Lebanon's existence and identity are at risk as a result of the influx of refugees.”

The March 14 General Secretariat slammed on Thursday Hizbullah chief sayyed Hassan Nasrallah, calling on the party to prioritize the higher interest of Lebanon.

“Nasrallah's speech focused on delusional victories in Iraq, Syria and Lebanon.... to secure some presidential and parliamentary interests,” the March 14 said in a statement after its weekly meeting.

Syrian warplanes staged four raids on Wednesday on the outskirts of the border town of Arsal in northern Bekaa, the state-run National News Agency reported.

The area of Wadi Hmeid was targeted for the second time in less than two days.