PHNOM PENH (Reuters) - China has lent Cambodia $259 million to build a new road in the capital Phnom Penh with Cambodia describing relations between the two countries as being at the “best stage” ever.

Cambodia’s long-serving Prime Minister Hun Sen is China’s strongest regional ally. He looks set to win a general election on July 29 and extend his 33-year rule after the main opposition was dissolved last year at his government’s request, prompting criticism from the international community.

China’s backing has bolstered Hun Sen in the face of criticism over what his opponents have said amounts to his destruction of democracy ahead of the election.

The concessional loan agreement was signed on July 10 between the Export-Import Bank of China and Cambodia’s Ministry of Finance to build a four-lane, 47 km (25 miles) city ring road, the finance ministry said in a statement on Friday.

“The signing is another new, fruitful and comprehensive strategic partnership between the Kingdom of Cambodia and the People’s Republic of China,” the statement said.

The new agreement comes as China and Cambodia celebrated the 60th anniversary of their diplomatic ties.

“Looking back at 60 years of our diplomatic relations, I can state without a doubt that the relationship and cooperation between the two countries ... are at the best stage than ever before,” Cambodia’s Foreign Affairs Minister Prak Sokhonn wrote in a letter to his Chinese counterpart Wang Yi.

China has poured billions of dollars in development assistance and loans into Cambodia through bilateral frameworks and China’s Belt and Road initiative to build a new Silk Road.

That has attracted a flood of Chinese commercial ventures in the country, including casinos and special economic zones.

“China will continue to firmly support Cambodia in following a development path suitable to its national conditions,” Chinese Premier Li Keqiang said in a letter to Hun Sen on July 19.