Tripoli:  Muammar Gaddafi's son Seif al-Islam said in a speech aired on Sunday that the regime would not "abandon the fight," as rebels closed in on Tripoli and there was fighting and explosions in the city.

"We have a long breath. We are in our land and in our country. We will resist for six months, one year, two years and we will win," he said in the speech broadcast on state television, which said it was made a day earlier.   

"We will not submit, we will not abandon the fight," he said. "This is not the decision of Seif al-Islam or Gaddafi but the decision of the Libyan people.

He said the Gaddafi family "has paid the price, like all Libyans," and urged rebels to launch talks, saying: "If you want peace, we are ready."

Four strong explosions rocked the centre of Tripoli early on Sunday. Witnesses also reported clashes in several quarters between insurgents and Gaddafi supporters.