A US-based rights group says Israel violated laws of war in a series of airstrikes during an eight-day military operation last November against the Hamas militant group in the Gaza Strip.

Human Rights Watch says it counted 14 airstrikes in which there didn’t appear to be a valid military target, and four others that targeted militants but used disproportionate force.

HRW says the attacks killed more than 40 Palestinian civilians. It cites a bomb attack on a Gaza home that killed a father and two children, ages 4 and 2. The group released the report late Tuesday.

Israel’s air assault came after increased rocket fire and other attacks by Gaza terrorists on Israel’s south.

A previous report by HRW late last year accused Hamas of war crimes for firing over 1,500 rockets at Israel and causing the deaths of civilians in Israel and Gaza during Operation Pillar of Defense.

That report also blasted terrorists for putting Gaza residents in the line of fire. The nongovernment organization’s research in Gaza found that armed groups repeatedly fired rockets from densely populated areas, near homes, businesses and a hotel, unnecessarily placing civilians in the vicinity at grave risk from Israeli counter-fire.

Also in December, the group pounded Israel for journalists’ deaths in Gaza during the conflict.

The military had no immediate comment. In the past, it has accused Hamas of using civilians for cover.

The Israeli watchdog group NGO Monitor said, however, that HRW possessed “neither the military expertise nor the appropriate fact-finding methodology” to make its assessments and conduct proper investigations. “Such judgments require knowledge of the military intelligence possessed by Israeli commanders at the time of the strikes, and information on intent of the officers. In contrast, HRW’s ‘evidence’ consists solely of its inability to identify ‘indication[s] of a legitimate military target at the site at the time of the attack’ and Israel’s refusal to explain its operational decisions to the NGO.

NOG Monitor also noted that HRW’s latest press release was “its seventh document relating to the November 2012 fighting in Gaza and Southern Israel. The disproportionate obsession and political agenda are further seen by HRW’s decision to conduct ‘field investigations’ on that particular conflict, at a time when the UN estimated that over 10,000 people were killed in the Syrian civil war in the month of January 2013 alone.”

It also criticized HRW for failing to wait for a response from the IDF. Said NGO Monitor, “The real reason HRW does not want to wait for the IDF report is because it will demonstrate that HRW’s claims are baseless, as happened with Israeli responses to the 2009 Gaza conflict and the 2006 Lebanon War.”