Germany's foreign minister has said his country's intelligence agency will audit Qatar to help clear allegations Doha supports terrorism.

Earlier this year, Saudi Arabia, the United Arab Emirates (UAE), Bahrain and Egypt isolated Qatar diplomatically and economically after claiming it supports terrorist groups and implements policies that could jeopardise the equilibrium of the region. Doha has denied the allegations.

Sigmar Gabriel told German radio station Deutschlandfunk on Thursday (6 July) that Qatar had agreed to "open all its books" to Germany's Federal Intelligence Service (BND) and provide answers "if we have questions about certain people or structures," AP reported.

Gabriel made the remarks one day after Arab leaders met in Cairo to discuss how to solve the ongoing Gulf crisis. However, they decided to continue with the ongoing embargo, following Qatar's rejection of a list of demands it was told to meet to end its isolation.

The demands included closing state-funded news outlet Al Jazeera, closing a Turkish military base and reducing ties with Iran, a regional adversary. Doha said it was reviewing the list, but added it was not actionable.

"I think we've made progress, but the crisis is far from solved. Now we can start looking into the (terror) allegations," said Gabriel. He added that there are no reasons to fear the crisis could escalate into a military operation.

In June, Gabriel deemed as "provocative" the list of demands given to Doha, arguing some of them challenge the country's sovereignty. He also said Germany remained in close touch with all sides involved in the crisis.

The United Nations undersecretary general, Jeffrey Feltman, met Qatar's minister of state for foreign affairs, Sultan bin Saad Al Muraikhi, on Thursday. He expressed concern over the continuation of the crisis and stressed the UN support of Kuwait for its mediation efforts to solve the situation, Al Jazeera reported.

The diplomatic and economic isolation of Qatar has sparked what has been deemed one of the worst crises in the Gulf in recent years.

It prompted Qatari citizens to stockpile goods amid fears food and water stocks would deplete as the country depends on food imports.

Iran and Turkey, which support Doha, have dispatched food supplies to Qatar. Ankara also sent a small contingent of soldiers and armoured vehicles. The two countries also deemed the list of demands given to Doha as "disrespectful" and "unacceptable".

In a separate development, a UK-based think tank on Wednesday accused Saudi Arabia of funding terrorists in Britain and called on the UK government to investigate Riyadh's alleged links to Islamic extremism.

The Saudi embassy in London said in a statement sent to IBTimes UK that the claims contained in the report were "baseless" and "categorically false".