RIYADH, March 12 (Reuters) - Saudi Arabia will watch Iran's behaviour during the two-month window agreed upon to restore relations, Saudi columnists said on Sunday, reflecting continued wariness in the longtime rivalry between the region's Sunni Muslim and Shi'ite powers.
The breakthrough on Friday brokered by China, a major trade partner of both countries, followed several rounds of Saudi-Iranian talks held in the region in a bid to contain tensions, at a time of Gulf frustration over what they perceive as gradual U.S. disengagment from the region.
Tehran and Riyadh said they had agreed to resume diplomatic relations and re-open embassies within two months, adding that their foreign minister would meet to implement the deal, without mentioning a more detailed timeline.
"The two-month period ... is the first test of Iran's credibility and proof of good intentions as we must see the start of real change in the regional landscape and a real correction in its dealings with the Kingdom," Saudi columnist Hamoud Abu Taleb wrote in Okaz, a Saudi daily.
A main source of tension is Yemen, where Riyadh leads a military coalition that has since 2015 been battling the Iran-aligned Houthi movement -- which has during the war launched missile and drones at the kingdom.
Abdullah al-Otaibi, in an Op-ed in Saudi-owned Asharq Al-Awsat newspaper, agreed the timeline to reopen embassies would "test" Iran's commitment and said Beijing could play a more effective role than "failed" Western efforts with Tehran.
Gulf states have grown increasingly disillusioned with key ally and security guarantor the United States, including over global powers' 2015 nuclear pact with Iran which they deemed flawed for not tackling Iran's missile programme and proxies.
Saudi Arabia and the United Arab Emirates have moved to assert more control over regional stability by pursuing conciliatory foreign policies they hope will allow them to focus on economic priorities.
"It is natural to have diplomatic ties even if at a low level because Iran's expansionist approach has created many touch points with Saudi Arabia....(But) we have to keep our eyes open," wrote Saudi columnist Tariq al-Homayed.
"China is the guarantor for this agreement. This will be important if Iran does not comply," he added.
The United States has voiced reservations about deepening ties between Gulf states and its economic rival China, whose president attended a Gulf summit in Riyadh last year at a time of severe strains in the strategic U.S.-Saudi relationship.
Riyadh and Abu Dhabi have repeatedly said they are looking to diversify their strategic partners while pressing Washington for concrete commitments to regional security.
