Taipei's defence minister says pressure from the mainland was the main reason Singapore has refused a planned port call by two Taiwanese naval ships, a move that will likely strain close military relations between Taipei and the city state. Taiwanese Defence Minister Lee Jye confirmed yesterday that two ships had been forced to anchor outside Singapore for refuelling after the local authorities refused them permission to enter port. The two frigates, with a combined crew of 700, anchored off Singapore for two days from March 5 before continuing with port calls to seven allies. Admiral Lee said that pressure from the mainland was the main reason behind Singapore's decision not to allow the ships into port. But he also blamed the media for exposing the visit, which he said had given Beijing the opportunity to put pressure on Singapore. 'In our negotiations, we agreed that [the port call] would not be reported by news media. But the [visit] was exposed and [Singapore] said it was all in the media,' he told legislators yesterday. 'They were unable to resist the pressure.' Admiral Lee said although he had attempted to convince Singapore to allow the ships to dock, including writing a letter to Singaporean military authorities, the vessels had been asked not to enter the port. He said Singapore had allowed the vessels to anchor outside the port in order to take on supplies and fuel. But Taiwanese legislators were angered by the treatment the navy had received, saying it was an insult to Taiwan's 'national dignity'. 'It is a humiliation to our national dignity and insulting to all the nationals of the Republic of China,' opposition Kuomintang legislator Chen Chieh said. The legislators were upset because the Singaporean military has been using Taiwanese bases and training facilities for more than three decades in a programme of co-operation that is dubbed Star Light. A visit to Taiwan by Singaporean Prime Minister Lee Hsien Loong in the middle of last year infuriated the mainland, and since then the city state had chosen to ignore Taiwan in an attempt to patch up its relations with Beijing, they said. Local media reported that Singapore had also told Taiwan's air force to cover a Taiwanese emblem painted on a supply plane from the island that was used to ferry aid supplies to tsunami victims. Taiwanese Premier Frank Hsieh Chang-ting told the legislature yesterday the Defence Ministry should avoid using non-diplomatic allies as destinations for visits, saying there was a constant threat of mainland pressure making them difficult affairs. He called for an assessment of the incident's impact on relations between Taiwan and Singapore. Taiwanese Foreign Minister Mark Chen Tan-sun said that Singapore was more concerned about its relations with the mainland, and therefore 'speaks whatever the Chinese communists love to hear'. But he said Taiwan would handle the case carefully.