Transcript for Saudi-led coalition bombs packed market, killing 29 children on a school bus

Martha, thank you. Weo hea overseas now to Yemen. A deadlyoll that count ice bitter civil war. Strikeyhe s.-backed sai-led coalition D this carryin children school more than two dozen child among theabc's senior foreign correspondent Ian Pannell reporting once again on one of the T humanarian CSIs in W. Eporter: Tonight, age in yen,udi coaon bombs a packed market, kng children, wounding another . They were in a school bus heading to a picnic. Is young B id in a head wod. They gentlmove his sool as he Y hit head, they hit my head." Yen ry suffering the world's worst humanitarian cris. Thousands are dead, milli nestarvati, two warrings accusf war crim. As we when we sited earlier this year. You can see the intensity of the battles that were HT here. Is isn'the fst attack on civilians, and deit talk ofpeace, it T T. To tgon tonight says the U.S. Mitary was dictly involved I those air rikes. But it won't say if ameri bombs, intelligence and fuel it gives todi were used. This lest attack civilns includingo many cldren killed will raise more questions about .support.tom? Ian pannellonight with T horrific at.

This transcript has been automatically generated and may not be 100% accurate.