Donald Trump has picked sides in the Middle Eastern crisis, publicly accusing Qatar of bankrolling terrorism in a series of tweets overnight.

The US president's posts take credit for the d iplomatic embargo that six other Middle Eastern countries have issued against the tiny but very rich nation in the Arab peninsula.

"During my recent trip to the Middle East I stated that there can no longer be funding of Radical Ideology. Leaders pointed to Qatar - look!" he wrote yesterday morning, Washington time.

"So good to see the Saudi Arabia visit with the King and 50 countries already paying off. They said they would take a hard line on funding ...extremism, and all reference was pointing to Qatar. Perhaps this will be the beginning of the end to the horror of terrorism!"

Trump's tweets directly contradict his comments on Qatar when meeting with its leader, Sheikh Tamim Bin Hamad Al-Thani, only a few weeks ago.

"We are friends. We've been now for a long time indirectly, haven't we? And our relationship is extremely good," Trump said late last month.

"We have some very serious discussions right now going on. And one of the things that we will discuss is the purchase of lots of beautiful military equipment because nobody makes it like the United States."

If Trump was concerned about Qatar being a state sponsor of terrorism, he certainly wasn't showing it then.

Read more: Arab states cut ties with Qatar

Read more: Egypt boots out Qatari ambassador

Qatar may seem like a bit player in the world of Middle Eastern politics, but there's good reason Washington would not want Trump to alienate the gulf nation.

As a long running ally in the region, Qatar plays host to the largest American air base in the Middle East. That base is home to about 11,000 troops and is the staging ground for American attacks on Islamic State in both Syria and Iraq.

US Senate Foreign Affairs Chairman Bob Corker. (AAP)

Qatar is a big enough deal that the Senate Foreign Relations Chairman Bob Corker was stunned into silence when told of Trump's tweet.

Corker was speechless for about 10 seconds when reading from Trump's Twitter account, shaking his head as he did so.

Corker is no partisan Trump-hater, and was one of the leading contenders to be his Secretary of State.

But Congressmen Ruben Gallego had no qualms about speaking out against Trump and his Qatar tweets.

"The President illustrated his rank ignorance for all the world to see on Twitter this morning, almost certainly before the few adults in his entourage could speak sense to him," the Arizona Democrat said.

"I empathise with the professionals at the State Department, Defence Department, Central Command, relevant Embassies, and other organisations of the US Government that will have to clean up his mess."

One such person trying to clean up the mess is Ambassador to Qatar Dana Shell Smith.

"Seems like a good time to RT (retweet) this one," she wrote on Twitter, posting a story about Qatar's efforts to counter terrorist financing.

Qatar may be the richest country in the world per capita, but an embargo from its neighbours has the potential to be crippling to its economy.

Qatar's only land border is with Saudi Arabia, and most of the country's food supplies come in that way.

Yesterday Qataris rushed to supermarkets to stock up on necessities in the fear of food becoming scarce.

Imports of food will start coming in from Iran, so despite higher prices there's few worries that Qataris will be going hungry.

White House spokesman Sean Spicer has said the US wants "to see this issue de-escalated and resolved immediately".

Kuwait is expected to act as a mediator between Saudi Arabia and Qatar to settle the dispute.