The United Arab Emirates' ambassador to the United States said there was no military aspect to steps taken by Arab powers against Qatar but further economic pressure could be applied.

Saudi Arabia, UAE, Bahrain, and Egypt cut ties with Qatar and imposed stringent economic sanctions on Doha for allegedly supporting "extremism". Qatar vehemently denies their accusations.

Mixed messages from the United States, an ally to all parties in the crisis, also has appeared to complicate diplomacy in a crisis that has reverberated across the Middle East and beyond.

"There is absolutely no military component to anything that we are doing," UAE Ambassador Yousef al-Otaiba told reporters in Washington on Tuesday.

He said he had been in contact several times with US defence chief Jim Mattis to assure him the American military base in Qatar, Al-Udeid, would not be affected by the crisis.

READ MORE: Qatar-Gulf crisis - All the latest updates 

Otaiba said the measures against Qatar were not an attempt to have the base moved "but if anyone asks we'd be willing to have that conversation". He pointed out a defence accord the United States and the UAE signed last month would allow Washington to send more troops and equipment there.

Qatar and Turkey 'see eye to eye' in many regional issues

Moving US air operations would involve a massive undertaking by the US military, which coordinates its air campaigns in Iraq, Syria, and Afghanistan from Qatar. About 10,000 US troops are stationed at Al-Udeid.

The countries have designated dozens of people and entities with alleged links to Qatar as "terrorists".

When asked what further steps could be taken against Qatar, 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. And so there'll be an escalation of economic pressure, again, short of a policy shift or negotiations that lead to a policy shift."

Otaiba said the UAE, Saudi Arabia, Bahrain, and Egypt were compiling a list of demands for Qatar that would be "handed over to the United States fairly soon".

He said they would broadly address the three areas of support for "terrorism, meddling in the internal affairs of these countries, and attacks through Qatari-owned media platforms".

READ MORE: US - Gulf crisis trending in a positive direction 

Otaiba said the four nations were seeking a shift in Qatar's behaviour through economic and political pressure.

"It's not our goal to undermine the GCC [Gulf Cooperation Council] but at the same time we don't want a member of the GCC undermining us," he said.

US President Donald Trump stepped into the crisis by appearing to side against Qatar and accused Doha on Friday of being a "high-level" sponsor of terrorism.

Saudi Arabia and Bahrain welcomed Trump's demand for Qatar to stop supporting terrorism.

Otaiba said the White House was supportive of the Arab powers' position. Asked about Secretary of State Rex Tillerson's call for the UAE and other Gulf countries to take de-escalation measures to ease the crisis, Otaiba said: "That's not going to happen."

In Qatar, business as usual - Counting the Cost

Source: Reuters news agency