Yemen

The children were on a field trip when the airstrike hit their bus in Saada province, aid groups say. The coalition, which is backed by the U.S., says the strike was a "legitimate military action."

The move, which gives another 18 months of protection from deportation, comes after the Department of Homeland Security declined to do so for nationals from several other countries in the past year.

It's a timely question in the wake of attacks on civilians, aid workers and hospitals. Here's a guide to their history and their content.

So far, the fighting has stayed in Hodeidah's outskirts. But the relative calm isn't likely to last — and aid groups are desperately calling for its port to stay open for a country already in crisis.

The U.S.-backed coalition says it aims to oust Iranian-sponsored Houthi rebels, but aid groups warn of potentially high civilian casualties.

The U.N. pulled foreign staff from Hodeidah amid efforts to avert an attack by pro-government forces backed by the United Arab Emirates. A shutdown of the port could put hundreds of thousands at risk.

The international aid group says the cholera treatment center had clear markings and that it gave its coordinates to the Saudi-UAE-led coalition that carried out the strike.

"The executive order, at its heart, says Yemeni people are bad and they need to stay away. We say no! We are part of the fabric of the country," says a Yemeni-American whose mother was denied a visa.

The money was pledged by Saudi Arabia and the United Arab Emirates, two countries that have fueled the country's humanitarian crisis. Aid groups from Yemen and beyond weigh in.