Palestinian militant group Hamas uses a global financing network to funnel support from charities and friendly nations, passing cash through Gaza tunnels or using cryptocurrencies to bypass international sanctions, according to experts and officials.

Qatar’s funding for Gaza actually passes through Israel, a source familiar with the process said.

The funds are transferred electronically from Qatar to Israel. Israeli and U.N. officials hand-carry cash over the border to Gaza.

The cash is distributed directly to needy families and public servants in Gaza and each family or individual must sign next to their name that they’ve received the cash. One copy of that sheet goes to Israel, one goes to the UN and one goes to Qatar.

“Qatari aid to the Gaza Strip is fully coordinated with Israel, the UN and the U.S.,” the Qatari government official said.

In recent years, Qatar bought fuel from Israel for Gaza’s sole power station. It also sent Egyptian fuel that Hamas can resell, using the proceeds for salaries.