The United States on Tuesday offered $10 million for the capture of two fugitive gunmen convicted of the 2008 killings of a U.S. diplomat and his driver in Sudan.

American John Granville, who was working for the U.S. Agency for International Development (USAID), and his driver, Abdelrahman Abbas Rahama, a USAID employee, died in a hail of bullets on New Year's Day in 2008 in Khartoum.

The rival leaders of Sudan and South Sudan arrived in the Ethiopia Friday to push for progress on stalled economic, oil and security deals between the former civil war foes, officials said.

The summit between Sudanese President Omar al-Bashir and his Southern counterpart Salva Kiir comes despite accusations from Juba on Thursday that Khartoum had launched air and ground attacks inside South Sudan.

Sudanese troops clashed with South Sudanese forces along their restive border, South Sudan's army said Thursday, a day ahead of planned talks between the presidents of the two rival nations.

Sudanese planes also dropped bombs as the rival forces clashed on Wednesday in South Sudan's remote north Raja region in Western Bahr el-Ghazal state, said the South's army spokesman Philip Aguer.

Sudan's President Omar al-Bashir has agreed to attend a summit on Friday with his South Sudanese counterpart to push stalled economic and security deals, official media say.

The meeting, which the SUNA news agency said is slated for the Ethiopian capital, would be the first since Bashir and South Sudan's President Salva Kiir late September signed the deals which they hailed as ending the conflict but which have not been put into effect.

Two Jordanian peacekeepers have been freed after 136 days of captivity in Sudan's Darfur region, the African Union-U.N. mission to the troubled region said on Wednesday.

"They are safe," UNAMID spokeswoman Aicha Elbasri told Agence France Presse. "This is the longest hostage-taking incident (for UNAMID)."

A torrent of water surged Tuesday into Sudan's Blue Nile river as President Omar al-Bashir inaugurated the expanded Roseires dam, which officials say should help develop one of the country's poorest, insurgent-hit regions.

When Bashir arrived to open the Arab-funded, Chinese-built expansion before thousands of dancing and flag-waving residents, an arc of water poured through the flag-draped dam, sending spray into the air and rapids bubbling.

Rebels in Sudan's Darfur claim to have seized a district capital just days after saying they took control of a major town.

The Sudan Liberation Army's (SLA's) Abdelwahid Nur faction said late on Friday it had captured the government office and army base in Guldo district near Central Darfur state's Nertiti town.

"Armed groups" from South Sudan clashed with Arab tribesmen in Samaha, a flashpoint border region disputed by Khartoum and Juba, the Sudanese military said on Thursday.

The fighting occurred two days ago, army spokesman Sawarmi Khaled Saad told Agence France Presse.

Sudan's President Omar al-Bashir is willing to meet his South Sudanese counterpart to help put stalled security and economic agreements into effect, official media said on Wednesday.

Bashir "affirms his readiness to meet Salva Kiir in any time and place to speed up implementation of the Addis Ababa cooperation agreement", the SUNA news agency said in a brief report.

Two Eritrean opposition journalists in Sudan have been detained by Khartoum's intelligence service, an Eritrean opposition source said on Tuesday.

Abdalal Mahmoud of the Eritrean Center for Media Services (www.adoulis.com) and Haroun Adam, who has also written for the foreign-based opposition website, have been held since Monday, according to the Khartoum-based opposition source.