Two prosecutors behind a graft probe that targeted the inner circle of Turkish President Recep Tayyip Erdogan fled to Armenia via Georgia after an arrest warrant was issued against them, officials said Friday.

The Istanbul prosecutor's office on Monday ordered the arrest of Zekeriya Oz, Celal Kara and Mehmet Yuzgec on accusations of "forming an organization to commit crime" and "attempting to overthrow the government by force".

Republican presidential frontrunner Donald Trump on Sunday refused to apologize for a crude attack on a female Fox News journalist that sparked widespread outrage, insisting he was misunderstood.

The brash billionaire -- who is leading a packed Republican field of White House hopefuls -- found himself at the center of controversy after seeming to suggest that Megyn Kelly, one of the moderators of last week's presidential debate, asked him tough questions because she was menstruating.

Georgia decried on Tuesday Moscow's "creeping annexation" of its territory after Russian border guards moved border markers further into Tbilisi-controlled area, leaving a portion of an international oil pipeline in territory under Russian control.

The move left a small portion of the Baku-Supsa pipeline, which transports Caspian oil destined for Western markets, under Russia's effective control.

Georgian troops on Wednesday launched joint military exercises with United States marines and soldiers from four Eastern European NATO members, the pro-Western ex-Soviet nation's defense ministry said.

The drills dubbed "Agile Spirit 2015" are part of a "substantive package" of measures aimed at bringing Georgia -- which has long sought full NATO membership -- closer to the U.S.-led alliance's standards, the ministry said in a statement.

A U.S. warship arrived Sunday in Georgia's Black Sea port of Batumi on a training mission, the U.S. embassy said, sending a message of support to the NATO aspirant amid the conflict in Ukraine.

The U.S. 6th Fleet's guided missile destroyer USS Laboon "will conduct routine combined training with the Georgian Coast Guard," the U.S. embassy in Tbilisi said.

Up to 20 people are still missing after devastating floods killed at least a dozen people in the Georgian capital Tbilisi, with escaped zoo animals still on the loose Monday.

The government of the ex-Soviet republic said the death toll after the Vere river burst its banks on Sunday following hours of torrential rain stood at 12 on Monday morning. 

Lions, tigers and even a hippopotamus escaped from a zoo in the Georgian capital Tbilisi Sunday, adding to chaos caused by severe flooding that killed at least 12 people, officials said.

Police and soldiers were hunting down the animals, recapturing some and shooting others dead, while rescuers airlifted scores of people trapped by the floods.

Georgia has threatened to revoke pro-Western former president Mikheil Saakashvili's citizenship after he was granted a Ukrainian passport and appointed as governor of the strategic Odessa region.

Georgian President Giorgi Margvelashvili said Saakashvili's move, which according to the constitution, could lead to the loss of Georgian citizenship, "insulted our state."

A U.S. man pleaded guilty Wednesday to providing material support to Islamic State militants after attempting to travel overseas to join the group, the Department of Justice said.

Leon Nathan Davis was arrested in the Atlanta airport in the southern state of Georgia last October as he attempted to fly to Turkey.

The United States now launches a new investigation into suspected Islamic State group sympathizers almost every day, a senior official said Wednesday, underscoring the increased threat posed by the jihadist group.

Pointing to a significant uptick in cases linked to militants who now control swaths of territory in Iraq and Syria, the official warned Congress of "brinkmanship" over intelligence gathering powers that put national security at risk at a sensitive time.