North Korea launched at least two unidentified projectiles towards the sea on Tuesday, South Korea's military said, hours after the North offered to resume nuclear diplomacy with the United States.

The North's projectile launches and demand for new proposals were apparently aimed at pressuring the US to make concessions when the North Korea-US talks resume. North Korea is widely believed to want the US to provide it with security guarantees and extensive relief from US-led sanctions in return for limited denuclearisation steps.

The North Korean projectiles were fired from South Pyongan Province, which surrounds the capital city of Pyongyang, in the direction of the waters off the North’s east coast, according to South Korea's Joint Chiefs of Staff and Defence Ministry.

The military said South Korea will monitor possible additional launches by North Korea but gave no further details on what projectiles North Korea had fired.

Al Jazeera's Rob McBride in Seoul said the authorities had still to confirm the nature of the projectiles, which flew for about 330 kilometres before ditching into the sea.

Tuesday's launches were the eighth since late July and the first since August 24. The previous seven launches have revealed short-range missile and rocket artillery systems that experts say would potentially expand the country’s ability to attack targets throughout South Korea, including US military bases there.

On Monday night, the North's First Vice Minister of Foreign Affairs, Choe Son Hui, said North Korea was willing to resume nuclear diplomacy with the US in late September but that Washington must come to the negotiating table with acceptable new proposals. She said if the proposals did not satisfy North Korea, dealings between the two countries could come to an end.

President Donald Trump called North Korea's announcement "interesting."

"We'll see what happens," Trump said. "In the meantime, we have our hostages back, we're getting the remains of our great heroes back and we've had no nuclear testing for a long time."

There was no immediate comment from the White House following reports of the launches.

Al Jazeera