By Timour Azhari and John Irish

BEIRUT/DAMASCUS (Reuters) - U.S., French and German envoys have warned Syria's new Islamist rulers that their appointment of foreign jihadists to senior military posts is a security concern and bad for their image as they try to forge ties with foreign states, two sources familiar with the matter said. 

The warning from the U.S., part of Western efforts to get Syria's new leaders to reconsider the move, was delivered in a meeting between U.S. envoy Daniel Rubinstein and Syria's de facto ruler Ahmed al-Sharaa on Wednesday at the presidential palace overlooking Damascus, a U.S. official said. 

"These appointments will not help them with their reputation in the U.S.," the official said.

The foreign ministers of France and Germany, Jean-Noel Barrot and Annalena Baerbock, also broached the issue of foreign fighters drafted into the army during their meeting with Sharaa on Jan. 3, an official aware of the talks said. 

Reuters reported the appointments on Dec. 30. The envoys' comments on the appointments have not previously been reported.

Sharaa's armed group, Hayat Tahrir al-Sham, led an offensive that ousted former president Bashar al-Assad on Dec. 8 and has since installed a government and disbanded the Assad-era army. It is now making efforts to reconstitute the armed forces.

Late last year, it made nearly 50 appointments including at least six foreign fighters, among them Chinese and central Asian Uyghurs, a Turkish citizen, an Egyptian and a Jordanian, Reuters reported at the time. 

Three were given the rank of brigadier-general and at least three others the rank of colonel, a Syrian military source said.

HTS and allied groups have hundreds of foreign fighters in their ranks who came to Syria during the country's 13-year civil war, many of them followers of hardline interpretations of Islam. 

Foreign capitals generally view foreign fighters as a key security threat as they suspect that some may seek to carry out attacks in their home countries after gaining experience abroad.

Officials of the new Syrian administration have said foreign fighters made sacrifices to help overthrow Assad and would have a place in Syria, adding they could be granted citizenship.

The Syrian defence ministry did not respond to a request for comment. The German foreign ministry did not comment. 

A State Department spokesperson said Washington is in a continuing dialogue with the interim authorities in Damascus.

"Discussions have been constructive and have covered a wide range of domestic and international issues," the spokesperson said, adding there has been "tangible progress on counter-terrorism priorities, including ISIS."

'MIDDLE PATH'

During the war, some foreign fighters in Syria formed their own armed groups, while others joined established formations such as the ultra hardline Islamic State as it rampaged across Iraq and Syria before being beaten back.

Other groups of foreign jihadists joined HTS, which disavowed previous links to al-Qaeda and Islamic State and fought bloody battles against them before going on to spearhead the lightning advance that toppled Assad.

The U.S., European and Arab Gulf States are engaging with the new administration to try to push it towards an inclusive political transition and also to seek cooperation on counter-terrorism and limiting Iranian influence in the region.

But they remain wary of how the rebels-turned rulers will manage the country and have questions over how they will bring together disparate groups with varying views on the direction the new Syria should take.

The U.S. official and a Western source said that Damascus explained the appointments of foreign fighters by saying they could not simply be sent back home or abroad where they may face persecution, and it was better to keep them in Syria.

The U.S. official said authorities also explained that these people had helped rid Syria of Assad and some had been in the country for more than 10 years and so were part of society.

Diplomats said the U.S., European and Arab countries, particularly Egypt and Jordan, opposed the appointments because they suspected the moves could send encouraging signals to transnational jihadists.

Those appointed to the post of brigadier-general include Jordanian citizen Abdul Rahman Hussein al-Khatib and Chinese Uyghur militant Abdulaziz Dawood Khudaberdi, also known as Zahid. 

Zahid commands the Turkistan Islamic Party's forces in Syria, which seeks to establish an independent state in parts of China and which Beijing designates as a terrorist group. 

Also appointed was Egyptian militant Alaa Mohamed Abdelbaqy, who fled Egypt in 2013 and was sentenced to life in prison in absentia in 2016 on terrorism charges. 

He headed the al Qaeda-linked al Nusra Front in Egypt and was the main link between it and other al Qaeda-linked groups, according to Egyptian security sources. 

Syria-focused diplomats and analysts say the country's new rulers face a challenge balancing the interests and demands of many factions, including foreigners, with the demands of Western and Arab powers whose support they need to rebuild the country.

Aaron Zelin, Senior Fellow at the Washington Institute for Near East Policy, said the rationale from Damascus for appointing foreign fighters to the military was that they are trusted and loyal, but also that Syria's new rulers want to prevent them causing trouble in the country or abroad.

"Maybe this is a middle path that works for everybody that hopefully leads to nothing happening outside of the country, but also they become sort of part of just Syrian society now," Zelin said.

"But I imagine there will still be risks locally as well as concerns globally."

(Reporting by Timour Azhari in Beirut and John Irish in Paris; additional reporting by Maya Gebeily in Beirut, Humeyra Pamuk in Washington and Ahmed Mohamed Hassan in Cairo; Editing by William Maclean)