Tripoli, Libya (CNN) -- At least four explosions rocked the Libyan rebel-held town of Zintan on Sunday, as the foreign policy chief of the European Union arrived in the war-torn nation and a former U.S. congresswoman criticized American policy on Libyan state television. Rebels in Zintan, in western Libya, said they believe the explosions were from Grad rockets. It was not immediately clear whether any damage or casualties resulted. Meanwhile, Catherine Ashton, foreign policy chief for the European Union, arrived Sunday in the Libyan rebel stronghold of Benghazi, according to military sources in the opposition's National Transitional Council. Officials earlier said the European Union would open an office in Benghazi on Sunday.
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NEW: EU's Catherine Ashton says Gadhafi must leave and pledges support for Libyans
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NEW: "We must have a future for Libya," she says
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The western Libyan town of Zintan is rocked by explosions
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A former congresswoman rips U.S. policy on Libyan state TV
Secondly, by opening an EU office in Benghazi, "I bring the commitment of the EU 27 member-states and all of the institutions in support of the people of Benghazi and the people of @placeholder, for us to support you in the future that you wish to see for your country," she said.