By Frances Harrison
BBC News, Tehran
Iran's supreme leader, Ayatollah Ali Khamenei, has called for greater unity between Sunni and Shia Muslims amid continuing fears over Iraq.
The ayatollah said nations embraced the US out of weakness
He told a gathering of Shia and Sunni scholars the US and Israel were trying to sow seeds of sectarian division in order to bring insecurity to Iraq.
Ayatollah Khamenei also said Britain had become expert in dividing Muslims.
Iran is concerned it is being pitted against Sunni countries because it backs Shia groups in Iraq and Lebanon.
Ayatollah Khamenei was giving his first reaction to US President George W Bush's new strategy for Iraq.
Mr Bush has announced a tougher policy on Iran and more troops to disarm areas of Baghdad, like Sadr City, controlled by Shias.
Ayatollah Khamenei complained that the most unsafe areas of Iraq were those controlled by the US military.
He said there was a need for greater unity in the Islamic world to prevent some countries embracing the US and Britain out of weakness and fear.
He said different sects and factions were natural, but Britain, because of its long presence in the region, had become expert in dividing Muslims.