Barak (R) whispers to an Israeli soldier during a training session at Tzeelim army base in southern Israel.
In a statement issued by the Israeli Defense Ministry on Thursday, Ehud Barak said he would do everything in his power to block an inquiry against former Israeli defense minister Benjamin Ben-Eliezer and six other Israeli officials.
On July 22, 2002, Israel dropped a one-ton bomb over the al-Daraj neighborhood in the Gaza Strip and assassinated Salah Shehadeh, a leader of the Palestinian Hamas.
The incident killed 15 Palestinians, including Shehadeh, eight children and three women, and wounded more than 150 others.
"The minister intends to fight vigorously against the accusations in Spain and do everything possible to get the investigation dismissed," reads the statement.
The Spanish National Court on Thursday began assessing charges that were brought against the former Israeli authorities by the Palestinian Center for Human Rights (PCHR).
A court order on Thursday confirmed that initial evidence suggests that the bombing "should be considered a crime against humanity".
The court says it has asked Israel for information, but "as of today, Israeli authorities have not complied with the request for international judicial cooperation".
If the court rules in favor of the complainants, the suspects can be arrested upon entry into Spanish territory.