ANKARA/DUBAI (Reuters) - Turkish President Tayyip Erdogan on Tuesday denounced the isolation of Qatar by neighboring states as a violation of Islamic values and akin to a “death penalty” imposed in a crisis that has reverberated across the Middle East and beyond.

Erdogan’s comments marked the strongest intervention yet by a powerful regional ally of Doha eight days after Saudi Arabia, the United Arab Emirates, Bahrain and Egypt cut ties with Qatar and applied stringent economic sanctions on it.

Later on Tuesday, the UAE ambassador to the United States, which has an air base in Qatar, said there was no military component to the steps taken against Doha.

Qatar denies accusations that it supports Islamist militants and Shi’ite Iran, arch regional foe of the Sunni Gulf Arab monarchies.

“A very grave mistake is being made in Qatar; isolating a nation in all areas is inhumane and against Islamic values. It’s as if a death penalty decision has been taken for Qatar,” Erdogan told members of his ruling AK Party in Ankara.

“Qatar has shown the most decisive stance against the terrorist organization Islamic State alongside Turkey. Victimizing Qatar through smear campaigns serves no purpose.”

The measures against Qatar, a small oil and gas exporter with a population of 2.7 million people, have disrupted imports of food and other materials and caused some foreign banks to scale back business.

The UAE envoy, Yousef Al Otaiba, told reporters in Washington: “There is absolutely no military component to anything that we are doing.”

“I have spoken and seen (U.S. Defense Secretary) General (Jim) Mattis four times in the last week; we’ve given them our complete assurance that the steps we have taken will not affect in anyway Al Udeid base or any operations supporting or regarding the base,” Otaiba said.

Al Udeid Air Base in Qatar is home to more than 11,000 U.S. and coalition forces and an important base for the fight against Islamic State militants in the region.

The chairman of the U.S. Joint Chiefs of Staff, Joseph Dunford, told a Senate hearing that the rift between Qatar and its neighbors was not affecting U.S. military operations.

Qatar, which imported 80 percent of its food from bigger Gulf Arab neighbors before the diplomatic shutdown, has been talking to Iran and Turkey to secure food and water.

The world’s second largest helium producer, Qatar has also shut its two helium production plants because of the economic boycott, industry sources told Reuters on Tuesday.

Turkey has maintained good relations with Qatar as well as several of its Gulf Arab neighbors. Turkey and Qatar have both provided support for the Muslim Brotherhood in Egypt and backed rebels fighting to overthrow Syrian President Bashar al-Assad.

Iraqi Prime Minister Haider al-Abadi also criticized the measures imposed on Qatar, saying in Baghdad on Tuesday they were hurting the emirate’s people, not its rulers.

SAUDI FOOD SUPPLIES?

Gulf Arab states have issued no public demands to Qatar, but a list that has been circulating includes severing diplomatic ties with Iran, expulsion of all members of the Palestinian Hamas group and the Muslim Brotherhood, the freezing of all bank accounts of Hamas members, ending support for “terrorist organizations” and ending interference in Egyptian affairs.

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Some analysts say demands could also include closing down satellite channel Al Jazeera, or changing its editorial policy.

When asked what, if any, further steps would be taken against Qatar, the UAE’s Otaiba said: “We’ve designated 59 people and 12 entities; it’s likely that you could see designations of their bank accounts, and perhaps of the banks themselves.”

“The specific list is being drawn up and the reason it has not been completed and passed on yet is because there’s four countries involved,” he added. “Each country has their own set of lists, their own specifications and so we’re trying to compile and curate that into one master list and it should be handed over to the United States fairly soon.”

Otaiba reiterated the accusations that Qatar was supporting terrorism.

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“Doha has become a financial, media and ideological hub for extremism. Then it must take decisive action to deal once and for all with its extremist problem,” he wrote in an opinion piece for the Wall Street Journal published on Monday night.

Saudi Arabia’s foreign minister, talking to reporters during a news conference in Washington on Tuesday with U.S. Secretary of State Rex Tillerson, said Riyadh was ready to send food and medical supplies to Qatar.

The minister, Adel al-Jubeir, defended the Arab powers’ move against Qatar as a boycott, not a blockade, adding: “We have allowed the movement of families between the two countries ... so that we don’t divide families.”

There has been no breakthrough in Kuwaiti efforts to mediate in the crisis, but a U.S. official in the region said Kuwait was continuing with what is seen as a “slow, painstaking, deliberate” process focused inside the Gulf Cooperation Council.

“The parties are still defining what it is they want out of this confrontation ... It’s difficult to conduct negotiations if you don’t really know what everybody wants.”

INTERNATIONAL DIPLOMACY

Qatari Foreign Minister Sheikh Abdulrahman al-Thani said on Monday that Doha “still had no clue” why Arab states had cut ties. He denied Doha supported groups like the Muslim Brotherhood that its neighbors oppose, or had warm ties with their enemy Iran.

Turkish Foreign Minister Mevlut Cavusoglu said Erdogan would discuss the Gulf rift in a telephone call with U.S. President Donald Trump in coming days.

Turkey approved plans last week to deploy more troops to a military base it has established in Qatar under a 2014 agreement with the Gulf Arab state. The move was seen as support by regional power and NATO member Turkey to Doha.

In Moscow, the Kremlin said President Vladimir Putin and Saudi Arabia’s King Salman discussed the crisis in a phone call on Tuesday. The Kremlin said the dispute was not helping to unite efforts to try to find a Syria settlement or fight terrorism.