Sunday's suicide terrorism attack that killed at least five commanders of Iran's Revolutionary Guards Corps could have an impact far beyond the Islamic Republic's restive southeast border with Pakistan. Although the attack was orchestrated by the Sunni extremist group Jundullah — a separatist organization based among the Baluchi ethnic group that spans the Iran-Pakistan border and has for years conducted low-key terrorism strikes — many in Tehran blamed the bombing on a covert campaign by Western intelligence agencies to destabilize Iran. And that could cast a shadow over President Barack Obama's delicately poised effort to engage Iran in search of a solution to the nuclear standoff.A Revolutionary Guards statement on Sunday said the attackers had been supported by "the great Satan America and its ally Britain" and vowed revenge. The speaker of Iran's parliament, Ali Larijani, blamed the attack on "U.S. action" and "America's animosity against our country." The State Department repudiated any suggestion of U.S. involvement and condemned the attack. But focusing on the allegation of Western support for Jundullah may be a sign that hard-liners in Iran intend to use the attack for their own purposes, justifying a crackdown on internal opposition and possibly striking a more hostile pose in dealing with the U.S. as nuclear negotiations get under way.Sunday's strike appeared to have been aimed, in keeping with Jundullah's agenda, at escalating hostilities between the government in Tehran, dominated by Shi'ite Persians, and the Baluchi minority. The attack involved a suicide bomber entering a mosque in the city of Pisheen during a meeting between local Sunni and Shi'ite leaders that was organized by the Revolutionary Guards to improve dialogue between the two communities. A second bomber struck a vehicle containing several Guards officers. The dead included the lieutenant commander of the Guards' ground forces in all of Iran as well as the Guards commander of the Sistan-Baluchistan region.Despite the long-standing tensions between Tehran and the Baluchis — as well as other minorities that, together, make up almost half of Iran's population — the authorities were quick to blame the attack on outsiders. Besides condemning alleged Western support for Jundullah, the Iranian government sharply criticized Pakistan, from whose territory the bombers were said to have entered Iran, and demanded that Islamabad act against the group.While any suggestion of a U.S. hand in Sunday's attack may be far-fetched, Iran is basing its accusation on the covert program begun by the Bush Administration during its second term in office that allocated hundreds of millions of dollars to efforts at destabilizing the regime from inside Iran. And while President Obama came into office promising a new era of engagment with Iran, it's not clear whether the covert program was ever suspended. Former Bush National Security Council officials Flynt Leverett and Hilary Mann Leverett wrote recently in the New York Times of their conversations with Iranian leaders, saying "President Obama has had several opportunities to send ... signals [of good intent] to Tehran — such as ending Bush-era covert programs against Iran — but has punted." Iran has long suspected that groups such as Jundullah are supported as part of the covert campaign, and in 2007, ABC News alleged that Jundullah had secretly received advice and encouragement from U.S. intelligence officials.Even if Western powers are in fact entirely innocent of involvement in Sunday's attack, it could nonetheless cast a pall over the nuclear negotiations. Monday's meeting in Vienna to discuss the technical details of a plan to transfer much of Iran's stockpile of enriched uranium for enrichment abroad into harmless fuel rods is unlikely to be affected. But in future talks with the Western powers and Russia and China, Iran could take the bombings as a pretext to change the subject from its nuclear program, putting its own security concerns and accusations against the U.S. on the agenda. Back in Tehran, the attacks may fuel the arguments of hard-liners for a more uncompromising response to Western demands and reinforce the narrative of Iran being under external attack, which President Mahmoud Ahmadinejad and the Revolutionary Guards have used to justify the harsh crackdown on political-opposition activities.The Baluchi separatists who struck on Sunday may imagine their deed simply as the violent pursuit of a local objective, but in a region divided by a number of interlocking tensions that carry within them the seeds of conflict, politics often fails to remain local for very long.