German Foreign Minister Sigmar Gabriel told German public radio Deutschlandfunk on Thursday 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."

Gabriel has just returned from a three-day trip to the region that included talks in Saudi Arabia, Qatar and mediator Kuwait.

Riyadh and its allies - Egypt, the United Arab Emirates and Bahrain - severed all diplomatic and travel ties with Qatar last month over its alleged support for extremists and close relations with regional foe Iran.

Gabriel said that he had spoken to both sides, adding that the military escalation some had feared at the start of the Gulf standoff no longer appeared to be a risk.

Watch video 00:26 Arab states discuss Qatar crisis

Qatar boycott to continue

Foreign ministers from the four Arab states decided not to impose further sanctions on their regional neighbor when they met in Cairo to discuss the situation on Wednesday.

They had been expected to consider strengthening measures against Qatar after a deadline they gave to the tiny Gulf nation to meet 13 demands expired.

Saudi Foreign Minister Adel al-Jubeir said "the political and economic boycott will continue until Qatar changes its policies for the better."

Gabriel said the countries had reiterated calls for Qatar to cease its alleged backing of terror groups. The foreign minister added, however, that there was no mention of other demands the quartet had issued to end the blockade, including calls for Doha to reduce its diplomatic dealings with Iran and close a Turkish military base.

"I think we've made progress, but the crisis is far from solved," he said. "Now we can start looking into the (terror) allegations."

Gabriel is set to meet with US Secretary of State Rex Tillerson on the sidelines of the G20 summit in Hamburg on Thursday to discuss the Gulf crisis, the war in Syria and the Ukraine conflict.

nm/ng (Reuters, AP, dpa)