A US State Department official said China expects to put forward a Ukraine peace proposal on Friday

Ukrainian officials said more explosions occurred in the Russian-occupied city of Mariupol, a supply center and rear base for Moscow’s forces.

Petro Andriyushenko, an adviser to Mariupol’s mayor, said there were three explosions on Thursday.

The official, who is not in Mariupol but maintains communications there, said two strikes hit the area of ​​the Ilyich iron and steel plant. “Ukrainian armed forces accurately hit the bases of the occupiers,” he said on Telegram.

“There was a third explosion… I hit him near the airport. Again. We are finishing the job,” he added.

The adviser also said that Russian planes were flying over the city at several points on Thursday. According to video on social media and unofficial accounts, there have been several explosions across the city over the past two nights.

It is unclear what caused the explosions and how many air defenses are in operation. Mariupol lies outside the range of Western-supplied missile and howitzer systems operated by the Armed Forces of Ukraine.

The city is located about 80 kilometers (50 miles) from the nearest Ukrainian front line positions, which would be out of range of the M142 Highly Mobility Artillery Rocket Systems (HIMARS) and M270 Multiple Launch Rocket Systems (MLRS) provided to Ukraine.

Natalya Homenyuk, spokeswoman for the Ukrainian army in the south, said only that “at this point, we can only state that remoteness is a very relative concept. And what is considered so inaccessible is not always so. The direction of Mariupol is no longer accessible to us.” Absolutely “.

Ukrainian media indicated that the army may have domestically deployed a new missile system with a greater range.

More on the Russian presence in Mariupol: There has been a heavy build-up of Russian forces in and around Mariupol since November, according to Ukrainian officials and videos on social media.

In November, Andryushenko posted a video and commented that “Russia continues to mobilize military personnel in the Mariupol region. At least 30 trucks with manpower move through Mariupol daily.” CNN cannot verify this number.

This week, Andryushenko reported that “the movement of military equipment towards Manush / Berdyansk has resumed. A column of at least 7 trucks carrying ammunition has been recorded moving through Mariupol towards Manush.”

Why is Mariupol important to Moscow: Analysts say the supply routes from Mariupol to the west and north are essential for the Russians to set up defensive lines in the neighboring Zaporizhia region against any Ukrainian counterattack.