North Korea conducts does it again, conducts another rocket engine test

North Korea has tested a new rocket engine as part of its efforts to build a missile capable of reaching the American mainland, US officials said.

Defiant North Korea has conducted another rocket engine test that can be used for an intercontinental ballistic missile or ICBM capable enough of reaching the U.S. mainland.

The technology used for putting satellites into space are the same ones used for an ICBM capable of reaching the west coast of the United States, Fox News quoted American officials as saying.

"While I greatly appreciate the efforts of President Xi and China to help with North Korea, it has not worked out. At least I know China tried!" Trump said in a tweet earlier this week.

The test follows about a dozen missiles launches this year, as well as three engine tests in March. The rocket test was allegedly conducted on Wednesday at the Sohae Satellite Launching Station, where similar tests of the rocket technology took place on three occasions in March.

According to unnamed U.S. officials there are signs of increased activity at North Korea's lone nuclear test site. "There are more people and more cars but nobody knows what that means," said the official.

U.S. spy satellites have detected new activity at North Korea's underground nuclear test site that involve some modifications around one of the tunnel entrances to an underground test area, U.S. officials said.

The officials said it is not yet clear if the activity indicates a sixth nuclear test is imminent, but noted there is concern that North Korea could set off a test during Wednesday's visit to Washington by top Chinese diplomats and military officials.

They also said that military options for North Korea have recently been updated, and will be presented to President Donald Trump for a decision to act if there is a nuclear test.