The ruling Al-Khalifa family put down a revolt last year using martial law and help from its regional allies. The violence, pitting Bahrain's Sunni-Muslim leadership against part of the Shi'ite Muslim majority, flared again in recent weeks.

Prince Salman bin Hamad bin Issa al-Khalifah told a conference on Middle East security in Manama on Friday that real progress can only come through face-to-face negotiations. Leading opposition groups said they were willing to take part.

"This will give the dialogue the popular and democratic momentum it needs to succeed," opposition groups including the main Shi'ite party Wefaq and leftist party Waad said in a statement in English on Wefaq's website.

Bahrain, where the US Fifth Fleet is based as a bulwark against Iran, accuses Tehran of encouraging the unrest. Iran, which is led by Shi'ite clerics, has denied meddling in Bahrain's affairs.

In his speech on Friday, Crown Prince Salman urged all political figures to condemn street violence but also said the government needed to push harder to reduce inequality.

King Hamad last year called for talks "without preconditions", but that initiative quickly stalled when Wefaq pulled out, saying its views were not being taken seriously.

The authorities have banned protests, saying they often lead to confrontations that block the streets, and revoked the nationality of 31 activists. Opposition groups say brutality and repression used to put down last year's revolt, which embarrassed Bahrain's western allies, continues.

"We demand that the authorities stop using excessive and systematic force against citizens," the opposition statement said.