YANGON (Reuters) - Myanmar leader Aung San Suu Kyi has declined an invitation to meet U.S. Secretary of State Rex Tillerson in Washington this week alongside top diplomats from Southeast Asia, citing other commitments, Myanmar officials said on Tuesday.

Myanmar State Counsellor Aung San Suu Kyi gives a news conference with European Union foreign policy chief Federica Mogherini (not pictured) in Brussels, Belgium May 2, 2017. REUTERS/Eric Vidal

Nobel laureate Suu Kyi - who serves as Myanmar’s foreign minister while also being de facto head of its civilian government - would send a senior official in her place, said Zaw Htay, director general of Suu Kyi’s office.

The Washington talks come amid signs members of the Association of Southeast Asian Nations (ASEAN), which includes Myanmar, are tilting diplomatically toward China as the Trump administration’s policy on the region remains unclear.

ASEAN foreign ministers are due to meet Tillerson on Thursday for talks covering trade, territorial claims in the South China Sea and crime, among other issues.

ASEAN stepped back from highlighting the maritime disputes between its members and China at a summit that concluded at the weekend, while Philippine President Rodrigo Duterte has sought closer ties with Beijing.

Myanmar’s President Htin Kyaw spent six days in China last month, signing an agreement that will see oil pumped through a pipeline across Myanmar to southwestern China, and Suu Kyi is due to visit Beijing for a summit on President Xi Jinping’s signature “One Belt, One Road” infrastructure program in mid-May.

Suu Kyi is barred from the presidency under Myanmar’s army-drafted constitution, but effectively leads the government through the specially created post of “state counselor”.

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“The state counselor won’t go to the U.S. because she has another meeting with the EU on that day,” Zaw Htay said.

The U.S. Embassy in Yangon had no immediate comment, and referred inquiries to the State Department in Washington.

Suu Kyi arrived in Brussels on Monday for the first stop of an official tour of Europe, where she will also visit Britain and Italy.

National Security Adviser Thaung Tun would go to Washington in her place, Zaw Htay said.

Diplomats in Yangon say President Donald Trump’s policy toward Myanmar - considered a success story of former President Barack Obama’s “pivot” to Asia - is so far uncertain.

Suu Kyi assumed power in 2016 following a landslide election win after Myanmar’s former military leaders initiated a political transition.

She traveled to the United States in September, when Obama agreed to drop all remaining sanctions against Myanmar, an international pariah for decades under junta rule.

Since then, Myanmar has been sharply criticized in the West over violence against minority Rohingya Muslims.

Kyaw Zeya, permanent secretary at the ministry of foreign affairs, said Suu Kyi was not planning to visit the United States in the near future.

But he dismissed the notion her absence from Washington was an indicator that ties were cooling in favor of China, saying Myanmar sought good relations with all major powers.

“We don’t promote relations with any country at the expense of another,” Kyaw Zeya said.