Iraqi troops mobilized to seal border crossings into Syria on Friday after Syrian rebels occupied government posts on their own side of the border.

A Reuters photographer saw Iraqi troops erecting concrete blast walls along their side of the border; he was told by Iraqi army officials that the structures were meant to prevent possible outbreaks of fighting, Reuters reports.

Iraqi officials are concerned not only with security on their own territory; they also seek to protect Iraqi citizens on Syrian soil.

If there is unrest at the border posts we are committed to protect our nationals when they enter Iraqi territory, said Iraqi government spokesman Ali al-Dabbagh to Reuters.

Iraq has sent planes to evacuate about 1,000 Iraqi nationals from the Syrian capital of Damascus, where rebel forces conducted a bomb attack that killed four high-level Syrian officials on Wednesday. Fighting in the city has reached new levels of violence.

A statement from Iraqi Prime Minister Nouri al-Maliki petitioned the United Nations for help.

We urge the United Nations for immediate intervention and cooperation with the Syrian authorities in order to protect the Iraqis and facilitate their return to their homeland, said the statement, according to the Associated Press.

In Syria, a popular uprising against President Bashar al-Assad began in March of last year following the regime's brutal crackdown on protesters across the country. Loosely organized opposition fighters have struggled against Assad's formidable forces for the past 16 months. The conflict has claimed at least 14,000 lives so far, and violence is ongoing.

So far, there are no reports of Syrian nationals attempting to cross over into Iraqi soil, despite their presence at least one border checkpoint station on the Syrian side.