The US embassy in Cairo said on Wednesday that the assasination of judges overseeing the second stage of parliamentary elections in North Sinai was an attack on "a symbol of the democratic process and Egypt's development."
On Tuesday, seven people -- including judicial officials and security personnel – were killed and eight injured in North Sinai's city of Al-Arish after attacks on the Swiss Inn hotel.
Sinai-based militant group, Ansar Beit Al-Maqdis, who swore allegiance to the ISIS group in 2014, claimed responsibility for the attacks.
"Egypt plays a crucial role as a factor of security and stability in the Middle East," the embassy's statement read, adding that the US "partners with and supports Egypt's security, stability and sustained development."
The governorate of North Sinai, along with twelve other governorates, cast their ballots on Sunday and Monday in the second stage of the country's parliamentary elections, with the results expected to be announced by Wednesday evening.
The Egyptian army has been battling an Islamist militant insurgency in parts of the North Sinai governorate for several years.
In October, the Egyptian Armed Forces spokesperson announced that Egypt's army had gained full control over the North Sinai areas of Al-Arish, Rafah and Sheikh Zuweid after successful raids on "terrorist strongholds" and weapons caches.
Relations between Cairo and Washington have warmed up in recent months after of a period of tensions following the ousting of Islamist president Mohamed Morsi in 2013.
The first stage of Egypt's parliamentary polls took place in October.
The parliament is expected to hold its first session before the end of this year.
Egypt has been without a parliament since the 2011 chamber, dominated by Islamists, was dissolved by a court ruling in June 2012.
President Abdel-Fattah El-Sisi, who was elected in 2014, has held legislative power in the absence of a parliament.