China's banks have tightened up on lending to Iranian importers in what is being seen as evidence that US pressure on Beijing to impose financial sanctions on Tehran is bearing fruit. A Tehran-based businessman told the Financial Times that banks once willing to provide lines of credit to underwrite China-Iran trade "now refuse to do so." The Iran-China Chamber of Commerce has sent a delegation to Beijing to discuss the issue. Another businessman said that Chinese banks prefer to work with traders who import goods to Iran through Dubai so the numbers appear in a less sensitive column on the country's trade ledger. The move comes not long after Stuart Levey, US Treasury undersecretary responsible for terrorism and financial intelligence, visited Beijing and pressed for tougher sanctions over Iran's nuclear program. The clampdown on bank lending wouldn't affect the export of Iranian oil, petrochemicals and minerals to China.