Egypt has taken delivery of two more US fast missile boats to boost its ability in ensuring "regional security and countering terrorism", the American embassy in Cairo said on Monday.

Ties with the United States plummeted after Egypt's army ousted Islamist president Mohamed Morsi in July 2013, with Washington freezing its annual $1.3 billion in military aid.

At the end of March Washington unfroze its military assistance but continued to denounce rights violations in Egypt and the repression of Islamists.

The two Fast Missile Craft reached the Mediterranean city of Alexandria on June 17, doubling Egypt's fleet of such vessels to four, a US embassy statement said.

The four ships, worth $1.1 billion, will contribute significantly towards "ensuring regional security, countering terrorism, and protecting global commerce", the statement added.

"The Fast Missile Craft directly supports maritime and regional security, which includes protecting vital waterways such as the Suez Canal and the Red Sea," said Major General Charles Hooper, a senior defence official at the American embassy.

"This delivery is a sign of America's ongoing commitment to Egypt and to our shared security interests in Egypt and the region," he added.

Since Morsi's ouster, hundreds of his supporters have been killed and about 40,000 arrested, according to the New York-based Human Rights Watch.

Hundreds of people have also been sentenced to death after mass speedy trials described by the United Nations as "unprecedented in recent history".