In October 1983, the United States led a military invasion of Grenada, a tiny Caribbean island nation, after a bloody coup ousted the government of Prime Minister Maurice Bishop, who was assassinated. President Ronald Reagan was said to have been concerned about a 10,000-foot-long airstrip that the communist country's military was building, which he thought would enable planes loaded with arms from Cuba to reach insurgents in Central America. The administration was also concerned about the safety of 800 American medical students studying in Grenada.

Grenada: Unilateral U.S. military action In October 1983, the United States led a military invasion of Grenada, a tiny Caribbean island nation, after a bloody coup ousted the government of Prime Minister Maurice Bishop, who was assassinated. President Ronald Reagan was said to have been concerned about a 10,000-foot-long airstrip that the communist country's military was building, which he thought would enable planes loaded with arms from Cuba to reach insurgents in Central America. The administration was also concerned about the safety of 800 American medical students studying in Grenada. AP

Since the Vietnam War, the United States has engaged in several military interventions. As the West looks ready to act against Syria, accused of using chemical weapons against its own citizens, here are 10 instances when America has intervened, sometimes without authorization from the United Nations. Produced by Anup Kaphle.

Since the Vietnam War, the United States has engaged in several military interventions. As the West looks ready to act against Syria, accused of using chemical weapons against its own citizens, here are 10 instances when America has intervened, sometimes without authorization from the United Nations. Produced by Anup Kaphle.

Since the Vietnam War, the United States has engaged in several military interventions. As the West looks ready to act against Syria, accused of using chemical weapons against its own citizens, here are 10 instances when America has intervened, sometimes without authorization from the United Nations. Produced by Anup Kaphle.

The Web site for the New York Times was inaccessible for some users Tuesday, apparently as the result of a malicious attack. Tuesday’s outage comes less than two weeks after the site suffered an outage that lasted approximately two hours.

The newspaper’s site was inaccessible for some — but not all — users starting at 3 p.m., and many users took to Twitter to ask if others were having similar problems reaching the site.

A Twitter account for the Syrian Electronic Army also claimed it has pulled a similar attack on Twitter. Twitter spokesman Jim Prosser confirmed that the company is looking into the report.

Twitter-owned sites appear to be functioning for the moment, though some users are reporting that they are unable to see images on the site.

The New York Times confirmed that its site is having problems, and company spokeswoman Eileen Murphy said that the outage is likely due to a “malicious external attack.”

View Graphic A look at the Syrian uprising nearly two years later. Thousands of Syrians have died and President Bashar al-Assad remains in power, despite numerous calls by the international community for him to step down.

“The site is down for some. We are working to fix the problem. Our initial assessment is that this is most likely the result of a malicious external attack,” she said.

Evidence of the attack can be seen through the domain name system, or DNS, entry for the New York Times. The DNS is essentially like a phonebook for the Internet that tells computers how to reach certain sites. The entry for the The New York Times is currently pointing to companies based in Moscow and Syria.

Sophos security researcher Chester Wisniewski confirmed that the name servers listed on the current directory entry are controlled by SyrianElectronic Army.com, and that the site does appear to be under attack.

“Depending on where you are in the world visitors to the Times are being redirected to servers in Syria that appear to be operated by the Syrian Electronic Army, a group infamous for attacking Western media organizations.” Wisniewski said in an e-mail.

The New York Times is continuing to publish stories despite the attack by offering users an alternative way to reach its site.

The New York Times outage follows other site issues the newspaper experienced two weeks ago. On Aug. 14, the company confirmed that its site had been affected by a “internal issue” that took the publication’s Web site offline for approximately two hours.

The Times has not offered further details about what may have caused that outage, but told The Washington Post at the time that it had “no reason to believe” the issues were the result of an outside attack.

August has been a particularly bad month for prominent outages. One day after the New York Times outage, several news Web sites, including The Washington Post, were affected by a breach at the third-party content provider Outbrain, which redirected some visitors to sites promoting the online activist group, the Syrian Electronic Army.

Google and Amazon have both been hit with technical problems that took down their Web sites. An Amazon Web Services outage this weekend also affected the performance of services including Netflix, Instagram and Vine.

Last week, Nasdaq was also forced to halt trading for three hours after a “technical glitch.”

There is no indication that these outages are connected.