US Defense Secretary Robert Gates said on Sunday he will seek to reassure Saudi and Egyptian leaders this week that Washington's diplomatic approach to Iran will not jeopardize long-standing ties to Arab states in the region. Speaking to reporters aboard his plane ahead of a visit to Cairo and Riyadh, Gates said there were concerns in the region about US efforts to engage Tehran that "draw an exaggerated sense of what's possible." "One important message will be particularly for the Saudis that any kind of outreach to Iran will not be at the expense of our long-term relationships with Saudi Arabia and the Gulf states that have been our partners and friends for decades," he said. US President Barack Obama has sought to open up diplomatic channels with arch-foe Iran in a bid to defuse tensions over its disputed nuclear program, but Gates said the White House had realistic expectations about what could be achieved. Gates also spoke to worries among Sunni-led Arab countries over Tehran's influence with the Shiite-dominated government in Iraq, calling for Arab states to make a greater effort to cultivate ties with Baghdad. During his visit to Cairo on Monday and Tuesday, Gates said he would discuss Cairo's attempts to stem smuggling through tunnels on its border with the Hamas-ruled Gaza Strip. Gates, who was due to have talks in Riyadh on Tuesday and Wednesday, said his visit was intended to maintain the strong ties Washington enjoyed with both Egypt and Saudi Arabia and that he wanted to renew the "very strong military-to-military relationships" with both nations.