Asian investors moved cautiously Tuesday as they returned to the trading floors after the long Easter break, with attention turning to a speech by Federal Reserve chief Janet Yellen later in the day.

After a broadly upbeat month across all asset classes -- which saw healthy gains after the sharp sell-offs of January and February -- investors also looked to cash in before closing their positions before the end of the week.

Oil prices fell in Asia on Tuesday as persistent concerns about a global oversupply and caution ahead of a U.S. stockpiles report chipped away at recent gains.

The commodity has seen healthy rises this month, after hitting near 13-year lows in February, thanks to a falling dollar and hopes that key producers will agree to output limits at an upcoming meeting in Doha.

The dollar climbed against the yen and euro in Asia as an upward revision of U.S. economic growth increased the chances of another Federal Reserve interest rate hike.

The greenback suffered heavy losses earlier this month after the U.S. central bank lowered its forecasts for tightening borrowing costs this year, citing the impact on the economy of a global slowdown and the January-February market turmoil.

Oil prices edged up in Asia on Monday, recovering slightly from last week's decline, but analysts said traders would likely delay any big moves until next month's meeting of key producers.

Hopes for an agreement between Russia, Saudi Arabia and other crude giants to at least freeze output sent both main contracts racing above $40 earlier this month, helped by a dive in the strength of the dollar.

South African President Jacob Zuma called for strengthening his country's economic ties with Saudi Arabia, during a visit to the kingdom on Sunday.

"While our political relations with Saudi Arabia are strong, our economic and trade ties should be reviewed and revitalized," he said in a statement.

Qatar's state-funded broadcaster Al-Jazeera on Sunday announced a fresh round of job cuts with around 500 positions being lost, most of them at the network's Doha headquarters.

On top of existing losses of 700 jobs following an announcement earlier this year that Al-Jazeera America is to close, it means the broadcaster is set to shed more than 20 percent of its global workforce. 

Six suicide attacks in eight months and a spat with Russia have added to concerns for the Turkish economy as tourists flee, taking billions of dollars in spending elsewhere, and foreign investors skirt the troubled country.

Days after a suspected Islamic State jihadist blew himself up on a top shopping street in Istanbul, hotels, restaurants and retailers in the city are counting their losses.

Iranian President Hassan Rouhani on Saturday called for regional connectivity and cooperation to boost economic growth and stability in the south Asian region.

On a two-day state visit to Pakistan which culminated on Saturday, Rouhani met with Pakistani Prime Minister Nawaz Sharif and held talks on matters of mutual interest including more connectivity between the two countries and a shared role to bring stability in the region.

For decades, Hong Kong thrived as an Asian business hub thanks to its killer combination of Western freedoms, independent courts and closeness to mainland China's booming market. Now political and economic ills from the mainland are eroding that edge.

Swedish-Chinese author Gui Minhai was counting on Hong Kong's freedoms when he chose the city as the base for the publishing empire he has built up over the past decade, churning out exposes on elite Chinese politics that were snapped up by visitors from mainland China, where they are prohibited.

It's early morning and the sun shines down on a line of cars in southern Spain waiting to cross into Britain... or rather its overseas territory Gibraltar where a potential Brexit has set alarm bells clanging.

Miles away from the debate gripping Britain over whether to leave or stay in the European Union, this rocky outcrop of 33,000 residents where fish and chips and double-decker buses are a fixture is nevertheless eyeing June's upcoming referendum with increasing alarm.