Chinese ships on U.S. navy "harassing" streak in South China seas

We're not sure why, but Chinese vessels seem to be on an angry, aggressive streak as of late - surrounding and tangling with United States vessels in international waters for seemingly no good reason. The most recent incident being with the U.S.'s USNS Impeccable.

According to the U.S. Department of Defense's release:

On March 8, 2009, five Chinese vessels shadowed and aggressively maneuvered in dangerously close proximity to USNS Impeccable, in an apparent coordinated effort to harass the U.S. ocean surveillance ship while it was conducting routine operations in international waters.

The Chinese vessels surrounded USNS Impeccable, two of them closing to within 50 feet, waving Chinese flags and telling Impeccable to leave the area.  Because the vessels' intentions were not known, Impeccable sprayed its fire hoses at one of the vessels in order to protect itself. The Chinese crewmembers disrobed to their underwear and continued closing to within 25 feet.

USNS Impeccable's master used bridge-to-bridge radio circuits to inform the Chinese ships in a friendly manner that it was leaving the area and requested a safe path to navigate.  A short time later, two of the PRC vessels stopped directly ahead of USNS Impeccable, forcing Impeccable to conduct an emergency "all stop" in order to avoid collision.  They dropped pieces of wood in the water directly in front of Impeccable's
path.

The incident took place in international waters in the South China Sea, about 75 miles south of Hainan Island.

It's not the first time this month that the Impeccable has been challenged (there were two previous incidents on March 5 and March 7 - no instances of mooning those times though), nor is it the only ship to have encountered bellicose behavior from Chinese vessels.

On March 4, a Chinese Bureau of Fisheries Patrol used a high-intensity spotlight to illuminate the USNS Victorious several times, and then Chinese surveillance aircraft conducted 12 fly-bys the next day. The American boat was allegedly conducting lawful military operations in the Yellow Sea.

A Chinese official has said the Impeccable was in their waters illegally, according to Reuters:

In response to U.S. claims that a naval ship was harassed by the Chinese side, the concerned official in China's embassy to the United States stated: The U.S. navy vessel concerned has been consistently conducting illegal surveying in China's special economic zone.

China believes this contravenes international laws of the sea and China's relevant laws. China has repeatedly used diplomatic channels to demand the U.S. side cease unlawful activities in China's special economic zone. China's law enforcement authorities have also sent vessels to carry out law enforcement activities.

The U.S. claim about operating in high seas is out of step with the facts.

We haven't seen such a bizarre instance of wonky military relations since just right after Bush took office in 2001 - when China forced a landing of a U.S. spy plane and the detainment of the plane's crew. Maybe this is a new tradition? Welcoming in new U.S. Presidents with a small reveal of military might mooning?