Nepal rolled out the red carpet on Saturday for China's President Xi Jinping as authorities rounded up Tibetans to prevent protests during his stay.
Xi is making the first state visit by a Chinese leader to Nepal in 23 years following his two days of talks in India.
President Bidhya Devi Bhandari received him at Kathmandu airport as the army band played the national anthems of the two countries.
Xi is expected to use his time in Kathmandu to push Beijing's controversial Belt and Road infrastructure projects.
The Chinese president said he would use the two-day visit to "renew friendship and explore cooperation with my Nepali friends" in a signed article published in Nepali newspapers on Friday.
"It is important that we adopt a strategic and long-term perspective and draw up a blueprint for our bilateral relationship to take it to a new height in this new era," Xi added.
The International Campaign for Tibet (ICT) said at least 18 people were arrested in the days ahead of Xi's arrival, including two Nepali shopkeepers selling bags with Tibetan flags or slogans. Fourteen remained in detention on Saturday.
Nepal is home to around 20,000 exiled Tibetans, but under pressure from Beijing the communist government has taken an increasingly hardline stance on their activities.
"There is heavy police presence, it is an intimidating situation. We've been asked to stay in," one Tibetan told AFP, speaking on condition of anonymity.
Nepal's authorities declined to comment.
- 'Focus on connectivity' -
Although India has traditionally been Nepal's main ally, China has intensified its presence in the impoverished Himalayan nation, pumping millions of dollars into infrastructure projects ranging from roads to hydropower plants.
In 2017, Nepal signed up to China's Belt and Road programme which includes initiatives to build or upgrade highways and airports in the country.
"A trans-Himalayan connectivity network is thus taking shape, which will serve not just our two countries but also the region as a whole," Xi said in his article.
Landlocked Nepal is seeking closer ties and much-needed energy and infrastructure investment from its giant neighbour.
"This visit has historic significance for Nepal. Our priority is to create opportunities for Nepal, joining it to China's development. We are focusing on connectivity between the two countries," said Nepal's Foreign Minister Pradeep Gyawali.
Although no official announcement has been made, it is expected that the two countries will sign agreements for Chinese investment in highways, tunnels and hydro projects.
High on the agenda is the extension of China's Kerung railway from the border to Nepal's capital Kathmandu. There have been warnings over the financial commitments however.
"Nepal has to be conscious when it reaches the point of financial dealings on these projects and build capacity to negotiate and not fall into debt traps," said Sudheer Sharma, editor of the Kantipur national daily.
Xi will hold talks with Prime Minister K.P. Sharma Oli and other top leaders and meet with President Bidhya Devi Bhandari.