An explosion in a mosque in southeast Iran near the border with Pakistan killed at least 20 people and wounded more than 55 others on Thursday, Iran's English- language channel Press TV reported.

The crowd had gathered at the mosque in the southeastern Iranian city of Zahedan to commemorate the death anniversary of the daughter of the prophet of Islam, Press TV reported on its website.

Police were investigating the blast and no group or individual has claimed responsibility for the bombing, it said.

Within minutes of the blast, a second explosive was founded and defused at the mosque, it added.

The mosque was partially destroyed by the blast and aid groups and medics rushed to the scene, Press TV's report said.

The official IRNA agency said that preliminary reports showed the explosion killed 15 people and wounded 50 others.

In the past few years, Iran has often been hit by bombings and armed attacks in its southeastern provinces bordering Pakistan and Afghanistan, which the authorities usually blamed on a Sunni rebel group called Jundallah.

Iran also blamed the United States, Britain and some other Western countries behind these attacks and accused them of destabilizing the Islamic Republic, a charge denied by Washington and London.

Clashes between Iranian security forces and drug smugglers were also frequent on the eastern border areas of Iran, which is located at the crossroad of international drug smuggling from Afghanistan, Pakistan to Europe.

(Xinhua News Agency May 29, 2009)