President Tayyip Erdogan on Sunday dismissed calls for Turkey to close a military base in Qatar and said a wider list of demands issued by four Arab states was an unlawful intervention against the Gulf emirate's sovereignty.

In his strongest statement of support for Qatar in the nearly three-week-old crisis centred on the Gulf state, Erdogan said the call to withdraw Turkish forces was disrespectful and that Doha ─ which described the demands as unreasonable ─ was taking the right approach.

Saudi Arabia, the United Arab Emirates, Egypt and Bahrain imposed a boycott on June 5 on Qatar and issued 13 demands including closing Al Jazeera television, curbing relations with Iran, shutting the Turkish base and paying reparations.

Doha said it was reviewing the list, but said it was not reasonable or actionable.

"We approve and appreciate the attitude of Qatar against the list of 13 demands," Erdogan, speaking outside a mosque in Istanbul, said. "...This approach of 13 demands is against international law because you cannot attack or intervene in the sovereignty of a country."

The demands are apparently aimed at dismantling Qatar's interventionist foreign policy which has incensed conservative Arab peers over its alleged support for Islamists they regard as threats to their dynastic rule.

Both Qatar and Turkey, whose ruling AK Party has its roots in Islamist politics, backed a Muslim Brotherhood government in Egypt before it was overthrown in 2013.

The Arab states have demanded Qatar cut any links to the Brotherhood and other groups they deem to be terrorist, ideological or sectarian.

Bahrain's state news agency on Sunday confirmed the demands set out by un-named Gulf officials on Friday, including that Qatar close the Turkish base, end military cooperation with Ankara inside Qatar and stop supporting militant groups.

"The demands aim to achieve regional countries' stability, stand firmly against foreign interference and stop support for terrorist organizations," it said.

'No pullout'

Turkey, the most powerful regional country to stand by Qatar, has sent 100 cargo planes with supplies since its neighbors cut air and sea links. It has also rushed through legislation to send more troops to its base in Doha.

Two contingents of Turkish troops with columns of armored vehicles have arrived since the crisis erupted on June 5, and Defence Minister Fikri Isik said on Friday that further reinforcements would be beneficial.

"The strengthening of the Turkish base would be a positive step in terms of the Gulf's security," he said. "Re-evaluating the base agreement with Qatar is not on our agenda."

Hurriyet newspaper said last week a joint exercise by Turkish and Qatari forces was expected following the Eid ul-Fitr holiday which started on Sunday, and the number of Turkish soldiers sent to the Gulf state could eventually reach 1,000. An air force contingent was also envisaged, it said.

Erdogan said Turkey had also offered to establish a military base in Saudi Arabia, but never received a clear answer.

"If Saudi Arabia wants us to have base there, a step toward this also can be taken," he told reporters. "I made this offer to the king himself and they said they will consider this."

"They did not come back to us since that day and even though they still didn't come back to us on this, asking Turkey to pull back its troops (from Qatar) is disrespectful against Turkey".

Speaking outside the Istanbul mosque after prayers marking the Muslim Eid ul-Fitr holiday, Erdogan said he would continue his planned program despite feeling briefly unwell.

"I had a little condition about my blood pressure, related to my diabetes," he said.