TOKYO, July 25 Kyodo - A group of Japanese and Koreans born to the victims of the 1945 U.S. atomic bombings agreed at a symposium Sunday to step up cooperation in urging the Japanese government to improve medical and welfare measures for them.

The government ''should work to grasp more accurately the situation surrounding us, the second generation of radiation victims,'' said Nobuto Hirano, who heads a nationwide group of second-generation victims in Japan.

In their fourth annual forum held in Tokyo, Hirano and others, including Lee Seung Deok, representative of the South Korean group, expressed hope that Japan will conduct health checks for them more frequently. Checks are currently offered only once a year, symposium participants said.

They also want the government to amend an existing law for supporting A-bomb victims.

The law compensates only Japanese radiation victims and babies in the womb of mothers who were pregnant at the time of the bombings. It does not extend to newborns or mothers who became pregnant after the attacks, as well as foreign nationals.

When Hiroshima and Nagasaki were bombed in the closing days of World War II in 1945, a number of Koreans and other foreigners were in the areas, where they were held as prisoners of war or as forced laborers.

The exact number of second-generation radiation victims is unknown, according to Hirano, who also said that as long as the Japanese are concerned, they were born to a roughly estimated 300,000 victims.

Researchers have noted the second generation can develop health problems such as cancer, hypertension, diabetes, and hardening of the arteries because of the radiation.

The Japanese government has not ruled out the possibility of radiation effects on the second generation, given studies by a Japan-U.S. research organization, Radiation Effects Search Foundation.

The foundation, however, also says it still needs more time to reach a definitive conclusion on the effects of radiation on the second generation of victims. ==Kyodo