Syria’s President harshly criticised U.S. and British aid to rebels and set harsh terms for talking to his opponents in a newspaper interview published on Sunday, as fighting raged across the country.

On the battlefield, rebels made significant gains in the heavily contested northeastern Syrian, capturing a police academy complex west of Aleppo and storming the central prison in the city of Raqqa, as well as a border crossing along Syria’s frontier with Iraq, activists said.

President Bashar al-Assad took a tough line against his opponents in the interview with London’s Sunday Times, dialling back earlier hints of flexibility about talks.

“We are ready to negotiate with anyone, including militants who surrender their arms. We are not going to deal with terrorists who are determined to carry weapons, to terrorise people, to kill civilians, to attack public places or private enterprise and to destroy the country,” Mr. Assad said. “We fight terrorism.”

Most opposition groups have rejected talks with Mr. Assad’s regime, with some demanding that he resign before talks can begin.

Mr. Assad said that he would not step down or go into exile. “No patriotic person will think about living outside his country. I am like any other patriotic Syrian,” he said.

The interview was conducted in Damascus last week and was published on Sunday, coinciding with U.S. Secretary of State John Kerry’s first foreign tour.

Mr. Kerry met with Syrian rebels in Italy on Thursday. He has announced a $60 million package of non-lethal U.S. aid to the rebels.

Mr. Assad said the “intelligence, communication and financial assistance being provided is very lethal.”

Mr. Assad also bitterly criticised Britain. He said instead of pushing for peace talks, British Prime Minister David Cameron’s “naive, confused, unrealistic” government was trying to end a European Union arms embargo so that the rebels can be supplied with weapons.

“We do not expect an arsonist to be a firefighter,” he said, dismissing any notion that Britain could help end the civil war, which has killed more than 70,000 people.

“How can we ask Britain to play a role while it is determined to militarise the problem? How can we expect them to make the violence less while they want to send military supply to the terrorists?” he asked.

On Thursday, British Foreign Secretary William Hague promised to increase support for the Syrian opposition, including equipment supplies and humanitarian assistance.

Mr. Assad said Mr. Hague was misguided in his offer of assistance to rebels. “The British government wants to send military aid to moderate groups in Syria, knowing all too well that such moderate groups do not exist in Syria,” he said.

“We all know that we are now fighting al-Qaeda, or Jabhat al-Nusra, an offshoot of al-Qaeda, and other groups of people indoctrinated with extreme ideologies,” he said.

Mr. Assad warned that arming the rebels would have grave consequences.

“Syria lies at the fault line geographically, politically, socially and ideologically. So playing with this fault line will have serious repercussions all over the Middle East,” he said.

“Retaliation does not mean missile for missile or bullet for bullet,” he said. “Our own way does not have to be announced.”

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