BEIJING/UNITED NATIONS (AFP/Reuters) - China on Tuesday again warned the United States against selling arms to Taiwan, amid media speculation that Washington could soon act on the islands request for new weapons. We firmly oppose the US selling arms to Taiwan, foreign ministry spokeswoman Jiang Yu told reporters at a regular briefing, saying Beijing has had serious consultations with Washington on the issue. We urge the US to recognise the gravity of selling arms to Taiwan... cancel any plans to sell arms to Taiwan and stop selling arms to Taiwan so as not to damage China-US relations. Taiwans President Ma Ying-jeou, despite warming ties with Beijing, has appealed to the United States for weapons, saying the island must stay on guard in light of the mainlands sharp rise in military spending. Taipei is reportedly seeking F-16 fighter jets as well as helicopters for military transport and rescue missions to modernise its ageing fleet, and US President Barack Obama is expected to act on that request in the coming months. Washington is the leading arms supplier to self-ruled Taiwan, despite switching diplomatic recognition from Taipei to Beijing in 1979. China and Taiwan split at the end of a civil war in 1949. Beijing still views the island as part of its territory awaiting reunification, by force if necessary. During his visit to China in November, Obama reiterated that the United States believed there was only one China. The United States is required by law to provide Taiwan with weapons of a defensive nature, under the Taiwan Relations Act. US defence firm Raytheon said last month that it had been awarded a contract worth 1.1 billion dollars for new Patriot missile systems to Taiwan, but that the missiles themselves would be part of a separate contract. Meanwhile, Chinas UN Ambassador on Tuesday made clear that Beijing was not ready to immediately support new sanctions against Iran, as called for by Western powers, saying the issue needed more time and patience. This is not the right time or right moment for sanctions because the diplomatic efforts are still going on, Chinas UN Ambassador Zhang Yesui told reporters through an interpreter.