The Saudi-led coalition, which is backing Yemen government forces fighting the Iran-allied Houthi rebels, prevented the United Nations flight from departing Djibouti on Tuesday because the journalists were due to travel.
Injuries were also reported, according to UNHCR, with a number of people taken to nearby hospitals.
Unusually in Yemen's fractured political landscape, Islah has supporters in the north and south of the country.Since the Saudi-led coalition intervened in Yemen in 2015, Islah has tried to distance itself from the Brotherhood, in deference to the government-in-exile's Saudi hosts.
Yemen's defenseless people have been under massive attacks by the coalition for more than two years but Riyadh has reached none of its objectives in Yemen so far.
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Tuesday's attack was the latest in a series of coalition bombings that have hit schools, hospitals, markets and private homes across northern Yemen.
Dr Abdullah al-Rabeeah, a former Saudi minister and now head of the country's state aid agency, told The Independent "there is no intention whatsoever to bombard or kill civilians".
Two million people are internally displaced in Yemen, many within their own governorates.
The UNHCR has said that this attack "demonstrates the extreme danger facing civilians in Yemen, particularly those attempting to flee violence".
"It is necessary to work closely to contain the cholera epidemic and prevent its outbreak in more Yemeni provinces and cities to avoid a possible humanitarian crisis whose consequences may last for years to come", said the AL chief in the statement.
"The people of Yemen are being subjected to deprivation, disease, and death as the world watches", Stephen O'Brien, the United Nations under secretary general for humanitarian affairs and emergency relief coordinator, said in a recent speech to the UN Security Council.