The US is preparing for a possible missile strike against the Syrian government, following reports of an alleged chemical attack launched earlier this week. As CBS News reports, an additional warship equipped with ballistic missiles was dispatched to the region late Friday, joining the three other ships currently there.

The move comes just days after hundreds of people died in what Syrian rebel groups claim was a chemical attack launched by the forces of President Bashar al-Assad. On Saturday, humanitarian group Doctors Without Borders said approximately 3,600 patients were treated with "neurotoxic symptoms" at three hospitals outside Damascus early Wednesday, following a series of rocket strikes. According to the organization, 355 of these patients died, though allegations of chemical warfare have yet to be independently confirmed.

The Obama administration has previously described the use of chemical weapons as a "red line" that would trigger US military intervention, though the White House has thus far been reluctant to deploy troops to the region, where a devastating civil war has killed more than 100,000 people over the past two years. Friday's dispatch marks the strongest show of force yet from the Obama administration, though US officials emphasized that the president is carefully weighing his options, and will only make a decision "once we ascertain the facts."

"our credibility is on the line."

Opposition groups insist that Assad was behind Wednesday's attack, which came just one day after a UN team of experts arrived in the country to investigate possible chemical strikes launched earlier this year. The Syrian government has steadfastly denied all accusations, branding them as a fabricated "distraction," though the incident has raised serious concerns among the international community. The US and other western governments are calling on Assad to allow for a full investigation into Wednesday's attack, with France and the UK directly accusing the regime of using chemical agents against its own civilians.

The Obama administration remains cautious, stressing that a quick military intervention would have potentially grave international consequences, though some members of Congress are pressuring the president to take action. Eliot Engel (D - NY), senior Democratic member of the House Foreign Affairs Committee, called for "direct intervention" in a letter published Friday, arguing that not doing so would set a dangerous precedent.

"a big event of grave concern"

"I am deeply concerned that if we do not enforce the red lines, our country and the international community will face several negative consequences because, our credibility is on the line," Engel wrote. "If we, in concert with our allies, do not respond to Assad’s murderous uses of weapons of mass destruction, malevolent countries and bad actors around the world will see a green light where one was never intended."

Speaking to reporters on Friday, Obama described this week's attack as a "big event of grave concern," but cautioned against rushing into an "expensive, difficult [and] costly" intervention. According to CBS News, Joint Chiefs Chairman Gen. Martin Dempsey is expected to meet with Obama at the White House today, where he will present various options for a strike against Assad.