Iraq is surprisingly the reason why Washington and Tehran could be working together US President George Bush has challenged Iran and Syria to prove they are serious about helping to quell deadly violence in Iraq. "These meetings will be an important test," Bush said, referring to Saturday's Baghdad conference. "They'll be a test whether Iran and Syria are truly interested in being constructive forces in Iraq." Saturday's meeting will include Iraq's neighbours as well as the five permanent members of the UN Security Council, the Arab League and the Organisation of Islamic Conference. Bush said there will be a subsequent meeting in early April of foreign ministers from around the world including US Secretary of State Condoleezza Rice, to discuss Iraq's future. US participation in the conference is regarded as a diplomatic shift after months of refusing to talk to Iran about Iraq. According to analysts, the about-shift is an attempt by the US to apply the recommendations of the Baker-Hamilton commission without openly declaring so. Three months ago, the commission recommended engaging both Damascus and Tehran in helping fix the deteriorating security and political situation in Iraq. Tehran said on Monday it was "not hostile" to joining its arch-enemy Washington at Saturday's meeting. The conference will be the first time Iranian and US envoys have publicly come together since a meeting at the Egyptian Red Sea resort in 2004 attended by then-US secretary of state Colin Powell and his Iranian counterpart Kamal Kharrazi. Iran's Foreign Ministry had stressed on Sunday that no direct talks were planned between Iran and the US at the Baghdad conference while the US Ambassador in Baghdad Zalmay Khalilzad said no decision had been made on the matter. However, Iranian Foreign Minister Manouchehr Mottaki made clear that Iran did have reservations about Saturday's conference. "The Iraqi side has been consulting us for the past 10 days and we pointed out some concerns," Mottaki said. "All participants at the conference should aim to help the people and government of Iraq without decision- making from outsiders," he added. Mottaki did not elaborate, but according to analysts Iran is concerned that at the conference both the US and Iraq might accuse it of supporting armed Shia groups in Iraq. Iran has said in the past it would be willing to discuss Iraq with the US, but tension has recently increased dramatically between the two countries. President Bush has stepped up accusations that Iran is backing Shia militants in Iraq. The US military has strengthened its presence in the Gulf and has detained a number of Iranians in Iraq. Washington is also leading a push for stronger sanctions against Iran over its nuclear programme. Against this backdrop comes the significance of last week's visit to Saudi Arabia by Iranian President Mahmoud Ahmadinejad, his first. During the Iranian-Saudi summit in Riyadh, Ahmadinejad and Saudi Arabia's King Abdullah agreed to work together to fight sectarian strife in the Middle East. The meeting was seen as more of an Iranian public relations offensive meant to help Iran improve its image at home and in the Arab world as its confrontation with the US escalates. It was also seen as a message to the US that the Gulf countries, despite their differences with Iran and their calls for a nuclear-free Middle East, are opposed to any strike on Iran and cannot afford another war in the region. Speaking on his return to Tehran, Ahmadinejad said the two countries would stand together against "enemy plots" seeking to divide the Muslim world. The Iranian-Saudi summit comes at a time of sectarian division between Saudi Arabia and Iran over events in Iraq and Lebanon. Saudi Arabia, a major Sunni power in the region, and Iran, an important Shia power, have found themselves aligned with groups on opposing political sides. Saudi Arabia has led a diplomatic drive in recent months to counter what it sees as Iran's growing influence in Iraq, Lebanon and the Palestinian territories. Still, there has been a recent flurry of contacts between Saudi Arabia, which is influential with Lebanon's Sunnis, and Iran, which backs Hizbullah and is also allied to Syria. "The two leaders asserted that the greatest danger threatening the Muslim nation at the present time is the attempt to spread strife between Sunni and Shia Muslims, and that efforts should be exerted to stop such attempts and close ranks," Iran's ISNA said. The agency quoted Ahmadinejad as saying he supported Saudi attempts to calm the situation in Lebanon and resolve the political crisis there. The two leaders also reportedly stressed the importance of Palestinian unity and the need to safeguard Iraq's independence and integrity. Speaking in Tehran after the talks, Ahmadinejad said: "We discussed the Palestinian and Iraq issues comprehensively. We have common views in this regard." However, Ahmadinejad's office on Sunday vehemently denied a report he had backed the Beirut Arab initiative for normalising ties with Israel on his visit to the kingdom. Ahmadinejad's visit and the Baghdad conference come at a time when Iran is under intense Western pressure over its nuclear programme. In a recent development on the nuclear showdown between Iran and the international community, Iran on Tuesday published an offer demanding an end to Security Council "interference" in exchange for clearing up suspicions about its disputed nuclear activities. The measure seemed an apparent attempt to head off new sanctions over Iran's refusal to halt uranium enrichment amid ongoing deliberations among the five permanent council members on a new resolution aiming to tighten sanctions against Iran for its "nuclear defiance". Signed by Ali Asghar Soltanieh, Iran's chief representative to the International Atomic Energy Agency (IAEA), the letter also said Tehran was ready to enter "constructive negotiations". The proposal was circulated on Tuesday at a meeting of the IAEA's 35-nation board in which Iran has been the main focus. The board reviewed a 22 February report from IAEA Chief Mohamed El-Baradie which declares Tehran has expanded enrichment. The board was expected to approve last month's decision by El-Baradie to suspend nearly half the technical aid his agency provides to Iran. Only North Korea and Saddam Hussein's Iraq have faced such punishment in the past.