North Korea threatens to strike back if the US initiates a hostile act against the communist regime amid rising tensions over the pursuit of a North Korean ship suspected of carrying weapons.

"As long as our country has become a proud nuclear power, the US should take a correct look at whom it is dealing with," North Korea's main newspaper Rodong Sinmun said in a commentary on Monday.

The paper also warned that "it would be a grave mistake for the US to think it can remain unhurt if it ignites the fuse of war on the Korean peninsula.”

The news comes as a US naval vessel is shadowing a North Korean ship believed to be heading for Myanmar via Singapore. The ship is suspected of carrying weapons in violation of sanctions agreed under a UN resolution.

Earlier, US President Barack Obama said Washington was "fully prepared" for a possible North Korean missile test.

Following a nuclear test and a number of short-range missile firing since May 25, the UN toughened sanctions against the country.

In April, Pyongyang also launched a long-range rocket which it said was to put a satellite into orbit. The US, however, said it was a ballistic missile test.

RZS/MD