The Syrian opposition website zamanalwsl.net reported on June 28, 2017 that Syrian President Bashar Al-Assad recently visited a new facility for developing and manufacturing long-range missiles that is under direct Iranian supervision, and met there with Iranian and Syrian experts. According to the report, the construction of the facility, which is located in Wadi Jahannam near the coastal city of Baniyas, began about a year ago, and it will begin operating at the end of this year. The report was accompanied by an aerial photograph of the area (see below).
It should be mentioned that, since the report appeared in an opposition website, its authenticity is uncertain.
The following are excerpts from it:
Aerial photograph that accompanied the report
"Reliable sources knowledgeable about the regime's 'scientific research' activities reveal that Assad's open and documented visit to the homes of some of his supporters in the Hama area was merely a cover for a secret visit to one of the most sensitive military facilities of the regime and its ally Iran. According to the sources [he] visited a new secret research facility whose construction began last year in a fortified area east of Baniyas, in a rugged valley called Wadi Jahannam. This deep valley is in the Tartous governorate, close to several villages belonging to the Baniyas administrative district: Al-Annaza, Nahl, Al-Alayqa and Al-Ghansala.
Map of the region (source: dd-sunnah.net)
"The sources mailed us aerial photographs of the area which show the facility, consisting of several buildings, and noted that it is under the direct supervision of the Iranians. It is a facility for developing and manufacturing long-range missiles, and the sources assess that it will be officially opened at the end of this year. According to them, during his visit to the facility Assad held an extensive meeting with several 'Iranian and Syrian experts,' lasting about two hours... They added that the Wadi Jahannam center is not just a new secret facility for developing and manufacturing weapons, but [was constructed] as part of [the regime's policy of] concentrating all the vital and strategic facilities in the areas [inhabited by] the sect loyal [to the regime, i.e., Alawite areas]."
 Zamanalwsl.net, June 28, 2017.
 On June 25-26, 2017, Assad made a visit to Hama, during which he attended an 'Id Al-Fitr prayer in one of the city mosques and visited the families of wounded Syrian army soldiers in the vicinity. The visit was extensively covered by the regime's official news agency. See SANA (Syria), July 25, 26, 2017.