BBC News with Sue Montgomery

Parliament in Nigeria has voted to send a delegation to Saudi Arabia to check on the health of President Umaru Yar'Adua. He's been in hospital there since November, being treated for heart trouble. As Will Ross reports from Abuja, there is a growing concern that the president's long absence is creating a power vacuum.
Up until now, only a handful of people close to President Yar'Adua have been kept abreast of his health condition. Even senior ministers have been kept out of the loop, and like the rest of the population have had to rely on rumours. But the calls for the president to step aside are growing, and the Nigerians are starting to make it clear that they find the continued absence and subsequent power vacuum unacceptable. President Yar'Adua has now been out of the country for 50 days. There had been no sight or sound of him until earlier on Tuesday when he spoke to the BBC over the phone from his hospital bed. He sounded very weak but said he hoped to get better soon and return to work.

The United States has dismissed as "absurd" allegations by Iran that American and Israeli agents were responsible for the assassination of a physics professor in Tehran. The official state media in Iran was quick to report details of the attack, and said a bomb had killed the scientist, Masoud Ali Mohammadi, as he was leaving his home. Jon Leyne reports.
The Iranian media said he was a nuclear scientist and a loyal supporter of the Islamic revolution. The clear implication was this was an attempt to derail the nuclear programme. But scientists in Britain and the United States said that from his published work, it was clear Mr Mohammadi specialized in another branch of physics and could not have been involved in the nuclear program. The Iranian opposition claimed that he supported one of their candidates during the presidential election. They will fear this killing might be used as a further reason to crackdown on their activities.

Saudi Arabia says four of its soldiers have been killed in clashes with Yemeni rebels who crossed the border into Saudi territory. The assistant defence minister said Saudi forces destroyed the rebels who tried to occupy a border village.

The European Court of Human Rights says British anti-terror legislation allowing police to search people without reasonable suspicion breaches human rights. The case was brought by two people who were stopped by police on the way to a demonstration in London in 2003. Here is Danny Shaw.
This is a strongly worded ruling from the European court that is likely to have far-reaching implications for the way British police use anti-terrorism "stop-and-search" powers. The measures enable officers to search anyone for terrorist material within specially designated areas. The court said the powers in the 2000 Terrorism Act were not sufficiently circumscribed, and did not contain adequate legal safeguards against abuse. It said there was a risk they could be misused against demonstrators and those from ethnic minority groups.

This is the World News from the BBC.

Russia has announced its biggest fall in gas production for 25 years. Gazprom, the energy giant that supplies three quarters of Russian gas, saw its output falls 16%. A spokesman blamed the global economic downturn for reduced demand in Russia and abroad.

The government in Venezuela is beginning power-cuts in large parts of the country to tackle an energy crisis caused by water shortages. The electricity minister said the cuts lasting up to four hours every other day would prevent water levels at Venezuela's main hydro-electric dam from falling too low. Drought has affected the flow of water into the reservoir.

Police in Mexico say they have captured one of the country's most wanted men, the alleged drug baron Teodoro Garcia Simental. His gang is blamed for much of the violence in the border city of Tijuana which escalated following his split from the powerful Arellano Felix cartel in 2008. Peter Bowes has the details.
Teodoro Garcia Simental was detained in La Paz, a fishing city on the Baja California peninsula. He is the second alleged major drug lord to be held in less than a month by President Felipe Calderon's government. More than 45,000 troops have been sent to drug hotspots to confront the cartels. The response has been more violence and an unprecedented number of killings. Teodoro Garcia is among 24 alleged drug kingpins wanted in Mexico, and the government had offered 2.1 million dollars for information leading to his arrest.

Figures from the United States' Central Bank, the Federal Reserve, show it made a record profit of 52 billion dollars in its lending operations last year. The Fed benefited from interest payments by private banks forced to take out emergency government loans during the global financial crisis. The figures suggest that the American tax payers have so far gained rather than lost money from the banking bail-out.