TEHRAN (AFP) - Irans President Mahmoud Ahmadinejad said on Thursday that the enemies of the Islamic republic were obliged to deal with his government, which had been returned to power with a thumping victory. Today, the enemies of the Iranian people are very angry because despite their propaganda the government is back in power with the support of 40 million votes, a defiant Ahmadinejad was quoted as saying by the ISNA news agency. We will not give these oppressive powers any advantage, and they are obliged to deal with this government, he said in reference to Western powers. Ahmadinejads disputed victory in last months presidential election triggered protests in Tehran and outrage among the global community, which has severely criticised the post-election crackdown on street protests. According to the official results, Ahmadinejad won with a 63 percent majority in the June 12 election out of around 39 million votes cast. Meanwhile, Iranian police fired tear-gas on Thursday as thousands of demonstrators defied government warnings and staged a march to commemorate the anniversary of bloody student unrest in 1999, witnesses said. Protesters chanted Death to the dictator as they gathered in the streets around Tehran University, the epicentre of the violence 10 years ago. Police deployed reinforcements after a first volley of tear-gas failed to disperse the demonstrators, who continued to grow in number, the witnesses said. Police then fired a second volley. Officers in riot gear had been out in force to try to stifle any gathering as the authorities remained on tenterhooks following the wave of protests over last months hotly disputed re-election of President Mahmoud Ahmadinejad that saw hundreds of thousands take to the streets. The authorities had warned of a harsh response to any commemoration of the 1999 violence in which at least one student was killed and dozens wounded when hardline vigilantes stormed student dormitories, according to an official toll. The warning was issued after the G8 world powers expressed serious concern over last months violence, which left at least 20 people dead. Groups of students have held small commemorative gatherings in previous years, but Tehran governor Morteza Tamadon issued a blunt warning for this years anniversary. If some people make moves that are contrary to security initiatives under the influence of anti-revolutionary networks, they will be trampled under the feet of our alert people, he told the official IRNA news agency. Witnesses said leaflets had been distributed in several Tehran squares urging people to join Thursdays march. Iranian authorities have banned all gatherings amid a fierce crackdown on protesters, reformists, journalists and political activists since the protests over the official results of the June 12 presidential election, which Ahmadinejads main challenger Mir Hossein Mousavi called a shameful fraud. An Iranian employee of the British embassy and a French lecturer also remained in custody, amid charges by the Islamic regime that Western governments have been interfering in the post-election disturbances, the most serious in its 30-year history. The French ambassador to Tehran, Bernard Poletti, met lecturer Clotilde Reiss in Tehrans notorious Evin prison on Thursday and found her in good physical condition, a diplomatic source told AFP. But she is rather preoccupied with what will happen next, the source added. In a strongly worded statement on Tuesday, French President Nicolas Sarkozy dismissed the espionage allegation levelled against Reiss as pure fantasy and called for her immediate release. Iran is also still holding one of nine British embassy local employees it arrested late last month on suspicion of stoking the unrest in the Iranian capital. A top aide to supreme leader Ayatollah Ali Khamenei said on Thursday that Britain and France were worse than the United States when it comes to interfering in Irans internal affairs. Ali Akbar Velayati, adviser to Khamenei on international affairs, accused Britain and France in particular of wanting to stop Irans nuclear drive. Western nations, especially France and Britain, want Iran to stop its nuclear activities. They want a weak Iran at the negotiating table, Velayati told the Fars news agency. Global powers led by Washington suspect that Irans nuclear programme is aimed at making atomic weapons but Tehran denies the charge, saying it is designed to generate energy. At a summit in Italy on Wednesday, the G8 issued a declaration expressing concern over the post-election violence in Iran but said they were determined to find a peaceful resolution to the nuclear standoff. G8 countries continued to be seriously concerned about recent events in Iran, it said. Interference with media, unjustified detentions of journalists and recent arrests of foreign nationals are unacceptable.