BERLIN (Reuters) - German Foreign Minister Sigmar Gabriel on Tuesday appealed to all sides in the Qatar crisis to hold direct talks to avoid a further escalation, and urged Iran to play a constructive role.

FILE PHOTO: German Foreign Minister Sigmar Gabriel gestures during a joint news conference with Palestinian Prime Minister Rami Hamdallah in the West Bank city of Ramallah April 25, 2017. REUTERS/Mohamad Torokman/File Photo

“The longer the crisis around Qatar continues, the deeper and stronger the lines of conflict will become,” Gabriel told reporters after a 90-minute meeting with Iranian Foreign Minister Mohammad Javad Zarif.

“We hope that there soon can be direct discussion among all those involved because a further escalation will serve no one.”

Gabriel said a 2015 agreement in which major powers lifted international sanctions against Iran in return for curbs on its nuclear program had helped avert military conflict. U.S. President Donald Trump has criticized the deal, but Gabriel said Germany and Europe would resist any efforts to cancel it.

He said Iran and Germany remained “worlds apart” on Israel’s right to exist, which he called “non-negotiable”, but that he and Zarif had open discussions about that issue and many others.

Gabriel said Iranian President Hassan Rouhani was trying to make Iran more attractive to foreign investors as part of a broad effort to improve the lives of the Iranian people.

But he said Iran could also improve its standing by helping to reduce tensions in the region.

Zarif said Iran was interested in working toward a political solution to the conflict with Qatar - which, unlike its Gulf neighbors, maintains good relations with Tehran - arguing that “pressure and sanctions and blockades” were not the answer.

Saudi Arabia, the United Arab Emirates, Egypt and Bahrain cut ties with Qatar on June 5, accusing it of support for Islamist militants, an allegation Qatar denies.

They have since issued 13 demands including closing Al Jazeera television, curbing relations with Iran, shutting a Turkish base and paying reparations.

Gabriel said he viewed the Arab list as the “starting point of negotiations, not the end”.

Zarif also invited Gabriel to visit Iran amid a push by both countries to expand business and trade ties. He said the German finance and economics ministers had pledged during his meetings in Berlin to use all means to strengthen trade.