Dandong city is the main crossing point to North Korea, and every day hundreds of tourists embark on small boats for a cruise on the Yalu border river and a fleeting glimpse of another world.

The boats approach within a few metres (yards) of the Korean shore, giving residents of the world’s second largest economy a view of their impoverished and sanctions-hit but nuclear-armed neighbour.

Further south, the border between North and South Korea is one of the world’s most heavily fortified. But the atmosphere is a great deal more relaxed along the Yalu river, even though the North’s ally China enforces a range of UN sanctions intended to curb its nuclear and missile programmes.

The sanctions have had a limited effect. After a huge military parade in Pyongyang on Saturday, the North Sunday defied international condemnation to test-fire another missile.

Tensions have been rising for weeks and the US has sent a naval strike group led by an aircraft carrier to the region. The North has reiterated it is ready for war with the US, and its army Friday vowed a “merciless” response to any provocation.

But the soldiers seen Sunday appeared notably relaxed — whether sitting on a bicycle, immersed in their reading or puffing on a cigarette next to women busily washing clothes in the river.

It’s a world away from the thousands of goose-stepping troops and missiles which packed Pyongyang’s Kim Il-Sung Square Saturday to mark the 105th anniversary of the birth of the nation’s eponymous founder.

Unconcerned at the prospect of provoking an incident, one Chinese tourist uses a slingshot to shoot a stone into the river as the boat approaches Sinuiju, the North Korean frontier town linked to Dandong by the Friendship Bridge.

From a green wooden observation post, a North Korean soldier placidly watches the tourists through binoculars.

The river cruises are an important money-spinner in Dandong, where dozens of boats offer trips for a modest 70 yuan ($10).

The cruise vessels stop off at a boat where an enterprising trader sells North Korean products: eggs, cigarettes and alcohol.

In the wider world the tensions persist. Sunday’s missile test was a failure, according to South Korea and the US military.

But it came hours ahead of a visit by US Vice President Mike Pence to the South, where the North’s weapons programme will top the agenda.