The number of Syrian refugees in neighboring countries has more than tripled since June to over 300,000, and by the end of the year that number will more than double again, the U.N. refugee agency warned Tuesday.

"The latest figures show a total registered population of more than 311,500 Syrian refugees in the four countries (Jordan, Lebanon, Turkey and Iraq). You might recall there were about 100,000 as of June," UNHCR spokesman Adrian Edwards told reporters in Geneva.

Baghdad on Tuesday moved to end Turkey's military presence in north Iraq where Ankara is pursuing Kurdish rebels, signaling a further deterioration in ties between the neighbors.

Turkey has since the 1990s maintained several military bases in the autonomous Kurdistan region of north Iraq, where the Kurdistan Workers' Party (PKK) rebel group also has bases.

Iraq stopped and searched a Syria-bound Iranian cargo plane for weapons on Tuesday, but allowed it to continue as no prohibited items were found, Iraqi officials said.

Washington has been pressuring Baghdad to ensure that all Iranian planes flying through its airspace are ordered to land and checked for weapons. This is the first time Iraqi officials have said that they have done so.

Saudi Arabia beheaded a Syrian on Tuesday for drug smuggling, the interior ministry announced in a statement carried by the official SPA news agency.

Abdulrahman al-Sweidan was "arrested as he was attempting to smuggle large quantities of narcotic pills into the kingdom," SPA reported.

An Internet video has surfaced appearing to show a U.S. reporter missing in Syria, in what would be the first direct sign of him since his disappearance in August.

Two news organizations which have employed the freelance journalist Austin Tice said the 47-second YouTube video did appear to show him, blindfolded, but that it lacked enough information to draw conclusions about his current condition or whereabouts.

Russia on Tuesday urged the West not to "search for pretexts" in order to conduct direct operations in Syria while also calling on Damascus and Ankara to exercise restraint along their flashpoint border.

"In our contacts with NATO partners... we call upon them not to search for pretexts to carry out a military scenario or initiatives like humanitarian corridors and buffer zones," Deputy Foreign Minister Gennady Gatilov told the Interfax news agency.

Israeli police arrested five people on Tuesday, two Israeli Jews and three Arabs, for disturbing the peace and attacking police at the compound where the Al-Aqsa mosque is located, police told AFP.

The arrests came as a group of rightwing Israeli Jews visited the compound, known as the Temple Mount by Jews and the Haram al-Sharif by Muslims. It is the third holiest site in Islam and is revered as Judaism's most sacred place.

International sanctions against Iran are biting but are not slowing the country's nuclear program, Israel's Strategic Affairs Minister Moshe Yaalon said on Tuesday.

"The sanctions and the pressure in place against Iran for around the past two years are effective, but the centrifuges continue to turn," Yaalon told Israeli public radio.

Turkish troops fired across the Syrian border on Tuesday, killing a member of a Kurdish militia and wounding two others in the first such fatal shooting at the Turkish frontier, a watchdog reported.

"The three Kurds, members of a Kurdish militia hostile to the Damascus regime but also wary of the rebellion, were patrolling the border in (Syria's) Hasaka province when they were hit by Turkish army fire from the other side," Observatory director Rami Abdel Rahman told AFP.

Five Yemeni army officers being held by a shadowy Islamist group in Syria are students at a military academy in Aleppo and are not involved in the fighting that has engulfed the country, a Yemeni official said.

In a statement released late Monday on the ministry of defense website, the unnamed official denied the officers had "any link at all, and they did not participate in the events in Syria."