Chinese President Xi Jinping led a major trade foray into Costa Rica Monday with agreements on projects worth nearly $2 billion, including upgrades of an oil refinery, a key highway and public transport.

"Relations between China and Costa Rica could well become a model of cooperations between countries of different sizes and national conditions," Xi said after meeting privately here with President Laura Chinchilla.

Costa Rica, the only Central American country that has diplomatic relations with China, was Xi's second stop on a quick swing through the region before an informal summit with US President Barack Obama in California Friday.

Xi and China's first lady, Peng Liyuan, were welcomed at the presidential palace by a bevy of school children, a tradition in lieu of military honors in Costa Rica, which is unique in Latin America in having no armed forces.

The biggest project will be the modernization of an obsolete oil refinery in the Caribbean port El Limon, which will be replaced with a new refinery capable of processing 65,000 barrels of oil a day.

The $1.5 billion venture will be financed with a $900-million credit from the China Development Bank, and the remaining $600 million will be put up by the China National Petroleum Corporation and the Refinadora Costaricense de Petroleo (RECOPE).

Another big project agreed to is the upgrading of Route 32, a strategic highway that links San Jose to El Limon, a $400-million dollar endeavor that will be financed by China.

The bilateral agreements include health protocols that will allow Costa Rica to export pork and dairy products to China.

China will also open lines of credit to Costa Rica for the purchase of 50,000 solar panels and to speed up the conversion of the country's public transport fleet to more environmentally friendly systems, Chinchilla said.

Xi also formalized the delivery of 8,400 computers to public school students and another 800 for teachers, under an agreement signed during a visit Chinchilla made to Beijing last year.

And he briefly got away from the formalities to visit a coffee plantation and taste some of the brew in Santo Domingo de Heredia. Xi doffed his jacket and toured the ranch with its owners who were not indentified, enjoying a coffee and light lunch.

On his arrival in San Jose on Sunday night, Xi said expanding cooperation with the Central American country will help both countries, as well as contribute to world peace, China's state news agency Xinhua reported.

Xi and his wife, a glamorous soprano singer who has stolen the spotlight during the trip, later were to attend a gala dinner hosted by Chinchilla.

After Costa Rica, Xi heads to North American neighbors Mexico and the United States for his first summit with Obama since taking office in March.

Xi previously made a three-day stop in oil-rich, English-speaking Trinidad and Tobago, where he met with Caribbean leaders for talks on trade and energy issues.

"What I found so impressive in the president of China is that he treated the leaders of small Caribbean nations no differently to how he would treat the president of (the) United States" or Britain's leader, Bahamas Prime Minister Perry Christie said.

China's growing interest in the region is "very constructive," said Dominica Prime Minister Roosevelt Skerrit.

"It's a signal to us in the Caribbean that China has been taking us seriously, they have responded to the solidarity we have expressed to them, particularly in the one China policy."

Separately, Chinese Politburo member Guo Jinlong was on an official visit to nearby Cuba, an island that Xi was not scheduled to visit.

China signed seven agreements with Cuba to increase bilateral cooperation on trade, transportation, tourism and biotechnology, state media reported.

In Guatemala, meanwhile, President Otto Perez said that he would visit Taiwan mid-month to discuss bilateral and development issues. He said he expects Taipei's assistance with a $100-million highway on the Caribbean coast.