The Japanese government said Monday it has urged its nationals in the Gaza Strip and surrounding areas to evacuate immediately as clashes between the Hamas militant group and Israel intensify.

The Foreign Ministry on Sunday raised its travel advisory to Gaza to the highest Level 4, which also warns Japanese citizens to avoid all travel to the areas regardless of purpose. The warning came as air raids by the Israeli military continue in response to rocket attacks by Hamas, which effectively controls Gaza.

"A volatile situation will continue as (Israeli) ground troops could invade," the advisory said.

It would be difficult for the Japanese Embassy in Israel to act quickly to aid Japanese nationals as movements are being restricted at Israel's checkpoints, the ministry said.

The ministry last issued an evacuation advisory for the Gaza Strip following the Israeli military's ground invasion of the area in July 2014.

On May 12, the ministry issued short-term safety information on Gaza and its surrounding areas, requesting Japanese nationals refrain from visiting while maintaining the travel advisory at Level 3, which warns against all travel regardless of purpose.