BEIJING — PREMIER Li Peng is visiting six Middle Eastern countries in an attempt to expand China's spotty diplomatic influence in the vital region, Western and Asian diplomats say.Beijing hopes the tour, which ends July 14, will position China as a socialist counterweight in the Middle East to the United States and other capitalist powers, the diplomats say. But China can muster only limited diplomatic leverage in the region. Although it is a major supplier of arms and one of the five permanent members on the United Nations Security Council, Beijing lacks the closely shared interests that its capitalist rivals have with many Middle Eastern countries, the diplomats say. Li's trip coincides with a meeting today between China and the four other permanent members of the Security Council in Paris to discuss ways to limit weapons sales to the Middle East. Reports from Cairo, the first stop on Mr. Li's trip, quoted Egyptian diplomats as saying that Li called for broad arms reductions in the Middle East. The Foreign Ministry in Beijing later denied that Li made such a proposal. China's conservative leaders are concerned that Moscow, because of its severe domestic problems, is neither willing nor able to check the expansion of US influence since the end of the Gulf war. As the self-appointed champion of the third world, China positions itself as the Middle East's defender against bullying by the US and other big capitalist powers, they add. But the Middle East exceeds China's grasp, the diplomats say. China's trade with the six countries on Li's itinerary - Egypt, Jordan, Iran, Saudi Arabia, Syria, and Kuwait - earned only $1.5 billion last year, according to official news reports. China mainly exports simple manufactured goods and imports fertilizers and basic chemicals. The trade is by no means critical to China and its trade partners in the Middle East. Moreover, China weakened its own diplomatic heft among some Arab countries by failing to take a militant stand against Iraq in the Gulf war, they say. China abstained on the UN resolution endorsing the use of force to eject Iraq from Kuwait. Finally, China's Middle East diplomacy has been comparatively shallow and brief. Although the official press has hailed contacts between China and the Middle East dating back 2,000 years, Beijing has only exerted a coordinated and energetic diplomacy in the region in the past decade. "They just don't have the contacts or experience in the region to pull off a big diplomatic initiative there," a Western diplomat says. China commands the attention of most of the countries Li is visiting because of its arms sales, diplomats say. For years China has followed Mao Zedong's policy to use arms shipments to acquire diplomatic influence. Since the early 1980s, it has put together an arms dealership making it one of the top five weapons sellers to the Middle East. Western diplomats are closely watching China's entourage for any officials tied to the arms industry.