Myanmar leader Aung San Suu Kyi arrived in Japan on Tuesday to court investment and aid, as an upsurge in violence against a persecuted Muslim minority at home posed the worst crisis of her six months in power and brought U.S. criticism.

Soldiers have poured into an area of northwestern Rakhine state in a crackdown on Rohingya Muslims after an insurgent group the government believes has ties to overseas Islamists launched a series of attacks.

Soldiers have been accused of raping and killing Rohingyas during the operation.

The crisis has sharpened tension between Suu Kyi's civilian administration and the army, which ruled the country for decades and retains major powers, and criticism of her is mounting.

The U.S. State Department said last week it had voiced concern to Myanmar about the reported rapes.

Suu Kyi's five-day visit to Japan is the latest in a whirlwind of foreign trips promoting her country as an investment destination. She has already been to China, the United States and India.

Myanmar needs Japanese investment and robust bilateral ties as a counterweight to China, its largest trading partner.

Japan, for its part, is eager to seek opportunities in meeting Myanmar's extensive infrastructure and development needs, a Japanese foreign ministry official told reporters.

During her visit, Suu Kyi will meet Prime Minister Shinzo Abe and Foreign Minister Fumio Kishida. She will also visit Kyoto, where she lived while doing research into her father, Aung San, Myanmar's independence hero.

Nearly 50 years of economic mismanagement by a military dictatorship has left the country's roads, airports and electricity supply shattered. This means there is little homegrown industry and Myanmar's recent annual economic growth of 8 percent has been mostly underpinned by imports.

In September, when Suu Kyi visited the United States, President Barack Obama announced he would remove most economic sanctions. Suu Kyi two weeks ago promised foreign investors a clearer legal framework and opportunities in untapped sectors.

Japan never imposed trade and financial sanctions against the country. As a result, Japan already has a significant presence, centred around the Japan-led Thilawa Special Economic Zone.

Thilawa, a 6,200 acre (2,500-hectare) industrial project on the outskirts of Yangon, the country's largest city, is about to begin its second phase of development in November.

In the fiscal year ending in March 2015, Japanese direct investment in Myanmar totalled $86 million, according to the Foreign Ministry.

Exports from Myanmar were worth $513 million, mainly clothing and agricultural products, while Myanmar imports from Japan were worth $1.3 billion, largely cars and machinery.