Chief of Palestinian Islamic Jihad Movement Ziad al-Nakhala on Sunday claimed the group was holding 30 Israeli prisoners as captives.
The website of Al Mayadeen Television, known to be close to the Hezbollah in Lebanon, published al-Nakhala's statement.
Saying that a total of 30 Israelis, including Israeli soldiers and settlers, were captured by the Palestinian Islamic Jihad Movement, al-Nakhala said the Israelis could only be released in exchange for Palestinian prisoners.
Palestinian group Hamas launched Operation Al-Aqsa Flood on Saturday, saying it was in response to the storming of the Al-Aqsa Mosque and increased settler violence. It said it fired rockets and captured many Israelis.
In retaliation, the Israeli army initiated Operation Swords of Iron against Hamas, launching airstrikes on the Gaza Strip. Fighting continued for the second day on Sunday as Israel declared a state of war, and continued airstrikes on Hamas targets.