Eritrea's Information Minister, Ali Ahmad, said on Monday Sudan had stepped up its attempts to disrupt peace and stability in his country.
He alleged Khartoum was continuing to pursue "its practice of governmental terrorism and assassination attempts against the president [Isaias Afworki]", but did not elaborate.
Already strained relations between the neighbouring states worsened considerably in 2002 when Khartoum accused the Eritrean government of supporting an offensive by Sudanese rebels on its territory.
The states' common border has since been closed.
Another cause of tension is Sudan's good relationship with Ethiopia, which fought a border war with Eritrea between 1998 and 2000. The peace process between Eritrea and Ethiopia has stalled.
Earlier in October, an Eritrean diplomat asked for political asylum in Sudan, protesting against what he described as worsening conditions back home.