The White House on Friday said North Korea recently provided Russia with a shipment of weapons, raising concerns about the expanded military relationship between the two countries.
The White House showed a series of satellite images that it said indicate cargo from an ammunition depot in North Korea (DPRK) was loaded on to a Russian-flagged ship and then taken by rail to a depot near Russia's southwestern border. The delivery took place between September 7 and October 1, the US said.
North Korean leader Kim Jong Un and Russian President Vladimir Putin met for a rare summit last month at which they discussed military matters, the war in Ukraine and possible Russian help for the secretive state's satellite programme.
In return for support, North Korea is seeking military assistance from Russia, including fighter aircraft, surface-to-air missiles, armoured vehicles and other advanced technologies, Kirby said.
The US is closely monitoring whether Moscow will deliver the weapons, but early signs of Russian ships offloading materials in North Korea may represent initial deliveries, he added.
The US said it will continue to enforce sanctions and make the case at the United Nations that the actions violate security council resolutions.
At least seven migrants have died, including one boy, one girl and two women, after their boat sank off the Greek island of Lesbos, Greece's coastguard said on Thursday.
The death toll from Myanmar's devastating earthquake has surpassed 3,000, with hundreds more missing, as forecasts of unseasonal rain presented a new challenge for rescue and aid workers trying to reach people in a country riven by civil war.
Russian forces unleashed an hour-long barrage of drones on Kharkiv, Ukraine's second city, late on Wednesday, triggering a number of fires but causing no casualties in the second such attack in the course of the day, the regional governor said.
Hamas decided not to respond or engage with Israel's counter-proposal for a ceasefire in Gaza, an official told Reuters on Wednesday, affirming it is committed to the mediators' plan instead.
Israel launched airstrikes on military airbases and infrastructure sites in the Syrian cities of Damascus, Hama and Homs on Wednesday, the Israeli military said.