Activists Kim Ah-hyun, left, and Kim Dong-hyeon speak to reporters at Incheon International Airport, Friday, following their release after being captured by Israeli forces aboard Gaza-bound aid flotillas. Yonhap The foreign ministry said Friday it has conveyed concerns to Israel over claims by two activists that they were assaulted by Israeli forces after being detained aboard aid vessels bound for the Gaza Strip.Earlier in the day, Kim Ah-hyun and Kim Dong-hyeon returned home via Incheon International Airport after being released by Israeli forces. They were detained and expelled after attempting to enter the Gaza Strip separately via vessels without authorization.Upon arrival, the two claimed that they were assaulted by Israeli forces."The government has conveyed our serious concerns to the Israeli side and will take measures commensurate with the gravity of the matter depending on the outcome of fact-finding efforts," the ministry said.The ministry said it "takes seriously" the testimonies by the activists that they were assaulted by Israeli forces.On Wednesday, President Lee Jae Myung criticized Israel's seizure of the vessels, accusing the country of violating international rules as the ships were not in Israel's territorial waters when they were seized.