The featured image in BBC’s website helps the readers show the tension, as the picture shows the missiles launched by North Korea. The image has low quality but good in authenticity, since it might be taken from the footage uploaded by N Korea.
The headline contains the answers to the question: what and who. The who is China and the ‘what’ is China made a call to North Korea about the missile/nuclear tests. North Korea is abbreviated to “N Korea”, since readers are assumed to know what it stands for, this also gives compactness without diminishing any attempt of conveying the main message.
China has proposed that North Korea suspend its tests of missile and nuclear technology to “defuse a looming crisis”.
The author chose to use the word ‘proposed’ here to show that China wants to negotiate in peace. It lessens the aggressiveness in China’s call to N Korea. Compare it if it were “China has demanded,” or “China has asked,” or “China has called”. The word ‘propose’ implies that proposition is just a suggestion/request without any kind of demands.