The radar-lock that a Chinese frigate put on a Japanese warship was “dangerous” and “provocative,” Japanese Prime Minister Shinzo Abe said yesterday, as tensions rose in a territorial row.

“It was a dangerous act that could have led to an unpredictable situation,” Abe told parliament. “It is extremely regrettable. We strongly ask for their self-restraint in order to avoid an unnecessary escalation.”

The hawkish prime minister, who took office in late December last year following a landslide election victory, described the radar-locking as a “unilateral provocative action by the Chinese side.”